Non Random Sampling — Transcript
Full transcript
- 0:00[Music]
- 0:08[Music]
- 0:14hello learners
- 0:15i am dr sabot sharwani working with
- 0:17indar gandhi national open university
- 0:19the topic which i am going to talk today
- 0:20is method of sampling part two
- 0:22which revolves around non-random
- 0:24sampling i think in our preceding two
- 0:26sessions
- 0:27if you recalculate yourself or you know
- 0:29visit the
- 0:30facebook live link you will find out
- 0:33that we
- 0:33the first session was you know talking
- 0:35about the sampling and when we have
- 0:36talked about the sampling we talk about
- 0:38how the sampling is
- 0:39quite important when we talk about the
- 0:41research when we talk about you know
- 0:42collection of data or when we talk about
- 0:44you know interacting with the
- 0:45respondents because
- 0:47there are certain mythologies which are
- 0:48going to play a very important role and
- 0:50then afterwards we have we have talked
- 0:52about you know the methods of sampling
- 0:54and talk about you know the first part
- 0:56which talks about the random sampling or
- 0:58rather we can say the probability
- 0:59sampling
- 1:00so in this probability sampling we have
- 1:02we have covered you know the various
- 1:03aspects
- 1:04that how the probability sampling
- 1:05differs from non-probability sampling
- 1:07or you know the random sampling differs
- 1:09from the non-random sampling so today's
- 1:11session you know talks about the
- 1:12non-random sampling
- 1:13which is also one of the important
- 1:15ingredients as far as you know the
- 1:16collection of data is concerned as far
- 1:18as the sampling is concerned so
- 1:20anyway prior to going into the depth of
- 1:21this topic let's you know quickly
- 1:23recapitulate ourselves what we have done
- 1:25in our preceding session
- 1:27and what exactly you know the points
- 1:28which had been taken care so that
- 1:30you know the blocks can be built and
- 1:32gradually we can
- 1:33mug up you know the the concept related
- 1:36to research or the research methodology
- 1:37or the statistical analysis so
- 1:40the first the very first lecture was
- 1:42talking about you know the curtain laser
- 1:43to research
- 1:44which usually talks about what exactly
- 1:46the research is and how research
- 1:49is going to play a very important role
- 1:50as far as the academicians are concerned
- 1:52as far as the academia is concerned as
- 1:54far as
- 1:54the corporate world is concerned or you
- 1:56know the present trading commerce is
- 1:57concerned
- 1:58because everywhere research is coming up
- 2:00in a big way and we have observed that
- 2:03there was a time when research was
- 2:04confined to to the university systems or
- 2:07to the
- 2:08academic institutions or the research
- 2:09institution but now it had crosses the
- 2:11boundaries
- 2:11and everywhere you find out even the
- 2:14most omnipresent thing which
- 2:16which the corporates are doing right now
- 2:17it's doing the research of the consumers
- 2:19or knowing about the behavior about the
- 2:21consumers so
- 2:23we are not going more into the depth of
- 2:25it because already we have a very
- 2:26thought provoking sessions which can uh
- 2:29provide a link to the
- 2:31learners to go through into that so then
- 2:33we have talked about the research
- 2:34thought
- 2:34how research thoughts are coming and how
- 2:37on the basis of you know the research
- 2:38thought you can build your
- 2:40future plan of action of research then
- 2:42there are certain faqs which are going
- 2:44to play a very important role
- 2:45like the frequently asked questions at
- 2:48that when we are going to the research
- 2:49when we are going to choose the title
- 2:51or when we are going to formulate the
- 2:53objectives or what could be the modus
- 2:54operandi behind that so this whole
- 2:56research methods talks about that then
- 2:58we have research plan research problem
- 2:59because
- 3:00while starting your research you know
- 3:01the certain problems comes into picture
- 3:03and so the planning is going to play a
- 3:05very important role and if you have
- 3:06planned the things in a very systematic
- 3:08manner i think
- 3:09up to some extent you can resolve your
- 3:11way of doing the things so
- 3:12then we have formulation of objectives
- 3:15how the objectives you know
- 3:16can be framed then hypothesis was there
- 3:18because this hypothesis is quite
- 3:20important because when you're going to
- 3:21into the depth of the research i think
- 3:23the the first building block is is
- 3:25they're used to
- 3:26is to you know having a null hypothesis
- 3:28or then you can
- 3:29work on the basis of these hypotheses
- 3:31which can extract from the objectives
- 3:33which we used to do so
- 3:34research design is there then collection
- 3:36of data is there which usually talks
- 3:37about you know sample
- 3:39uh secondary data and primary data and
- 3:41then sampling is there so
- 3:42in our last to last session we have
- 3:44talked about the sampling
- 3:46and the the very last session was random
- 3:49sampling so
- 3:50probability sampling is there so now
- 3:53uh the very important thing is that why
- 3:55we go for uh sampling this we have
- 3:57already talked about this is a very
- 3:58important aspect because universal and
- 4:00population is a very gigantic shape
- 4:02and it's really cumbersome for the for
- 4:04the individual for the researchers to
- 4:06you know
- 4:06go into the depth of all the population
- 4:08or the universal and come to the
- 4:09conclusion so
- 4:10that is where you know the the concept
- 4:12of the sampling comes
- 4:14and the collection of sample comes into
- 4:15picture so from there you know the
- 4:17things had need to be come up
- 4:18and then there are certain methodologies
- 4:21which are
- 4:22very important and when you talk about
- 4:23the random sampling we have already
- 4:25talked about you know the random
- 4:26sampling
- 4:26and we have seen that how the
- 4:28bifurcation of random sampling is there
- 4:30because
- 4:31uh the very important thing is that the
- 4:34that random sampling talks about you
- 4:35know the sampling outlier
- 4:37outlier is is a very important
- 4:39ingredient because
- 4:40when we study the statistics when we go
- 4:43into the depth of measure of central
- 4:45tendency
- 4:46there you know we have a very stereotype
- 4:48methods that is uh
- 4:50mean median and mode and these mean
- 4:53median modes
- 4:54lacks you know when the outlier comes
- 4:56because when you go for the average
- 4:58average in general you know are in
- 5:00certain intervals or you know
- 5:02link to one another but sometimes what
- 5:04happens when you take average sometimes
- 5:06you know the figure comes like 5 10 15
- 5:08and sometimes comes at 90.
- 5:09if you take average of all three i think
- 5:12the averages could be somewhat
- 5:13differs whereas if you so that that 90
- 5:16is nothing but
- 5:17outlier because it is different from
- 5:19from the other other sample numbers
- 5:20which you have taken so
- 5:22then you have then you are going to
- 5:24apply the measure of central
- 5:26standard deviation or measure or
- 5:28dispersion or other way of doing things
- 5:29so
- 5:30that is the model which is there where
- 5:32when you are emphasizing more on the
- 5:33random sampling i think the random
- 5:35sampling always emphasize on
- 5:37sampling outliers which is somewhat
- 5:39lacking so that is the reason you know
- 5:40we have to come out from there
- 5:42and we have to apply this
- 5:44non-probability sampling so anyway
- 5:47we are just going to throw a light on
- 5:49what exactly the non-random sampling is
- 5:51because
- 5:52when you talk about the sampling i think
- 5:54is a study of research involves a large
- 5:55number of population we have already
- 5:56talked about
- 5:57and you see universe is at the at the
- 6:00top then you have sensor then your
- 6:01sample population then
- 6:02sample frame and then from here from
- 6:05here you are going to
- 6:07take the elements or collect the data so
- 6:10these are the points which we have
- 6:11already covered in our preceding
- 6:12sessions
- 6:13and what could be the sample is what are
- 6:16the essentials of good sample then
- 6:17random sampling methods
- 6:18and and today we are going just focus on
- 6:22non-probability
- 6:23methods so when you are going to talk
- 6:25about the
- 6:26probability methods i think we have
- 6:28already talked about it's a random
- 6:29sampling does not involve human judgment
- 6:32requires sampling frame and the
- 6:35the you know the methodologies are
- 6:37systematic stratified cluster
- 6:39or you know the simple random sampling
- 6:41whereas when you talk about the non
- 6:43probability methods it is you know the
- 6:45it involves human judgment
- 6:47and it has sampling frame required and
- 6:49it is you know called the quota sampling
- 6:51convenience sampling judgment sampling
- 6:53or you know this snowball
- 6:56sampling so uh so we are going to
- 6:59gradually talk about and distinguish how
- 7:00this
- 7:01probability sampling refer differs from
- 7:04non-probability sampling because
- 7:05when you are going to talk about the
- 7:06probability sampling i think if you see
- 7:08this particular image
- 7:09this this probability sampling is quite
- 7:12scattered in nature whereas
- 7:13non-probability sampling is quite
- 7:14purposive in nature
- 7:16and and it is in a in a very systematic
- 7:18manner you are going to take so somewhat
- 7:20you know the
- 7:20model is like that whereas when you are
- 7:22going to talk about the probability
- 7:23sampling you are not
- 7:25biased whereas when you are going to
- 7:26talk about the uh this non-probability
- 7:28sampling you are very much biased
- 7:30so this is a thing which is there and
- 7:33now
- 7:34we have got a very very important
- 7:35comparison which can distinguish
- 7:38that what is the difference between what
- 7:39is the actual difference between you
- 7:40know
- 7:41the probability sampling and
- 7:42non-probability sampling and that is
- 7:44quite important because once you are
- 7:45going to depth of
- 7:46non probability sampling there must be
- 7:48certain logic there must be certain
- 7:50justification
- 7:51if you are not going to provide the
- 7:53justification i think some way you are
- 7:55going to lack because
- 7:56because what happened when we when we
- 7:58are in the process of
- 7:59collection of of data or taking the
- 8:02sample or extracting the sample
- 8:03i think this this phenomena need to be
- 8:06understand in a very
- 8:08contemporary manner so if you see this
- 8:11probability sampling is a sampling
- 8:12technique in which the subjects of the
- 8:14population get an equal opportunity to
- 8:16be selected
- 8:17as a representative sample we have seen
- 8:18in the cluster sampling we have seen in
- 8:21the you know
- 8:21the stratified random sampling that we
- 8:24make certain strata we make certain
- 8:26group
- 8:26and from that group you know some of the
- 8:28representation need to be done
- 8:30so there must be a model where equal
- 8:32opportunities need to be given
- 8:34and there must be a representative from
- 8:36e sample so that is the beauty of
- 8:38probability sampling which we have
- 8:40studied elaborately in our preceding
- 8:41session
- 8:42and if you talk about non-probability
- 8:44sampling i think non-probability
- 8:45sampling is a method of sampling wherein
- 8:47it is known that which individuals from
- 8:50the population will be selected as
- 8:51sample because
- 8:52so that could be the reason you know if
- 8:54you talk about probability sampling it
- 8:55could be
- 8:56not biased whereas non-probability
- 8:58sampling is quite biased because you
- 8:59talk about you know the convenient
- 9:00convenience sampling
- 9:02or you know judgmental sampling or the
- 9:03quota sampling
- 9:05or even the snowball sampling or
- 9:06purposive sampling so everywhere you
- 9:08observe that you know you are quite
- 9:10familiar that you are going to collect
- 9:12the data from from this manner
- 9:13and and that from this particular class
- 9:15increase so you are quite biased in that
- 9:18and if you talk about the convenience
- 9:20sampling
- 9:21you are you know for your convenience
- 9:23like you know
- 9:24you are doing your research in in delhi
- 9:27or in
- 9:27particular state so you have gone for
- 9:29the convenience sampling because you are
- 9:31reciting to that particular state and it
- 9:32would be easier for you to collect the
- 9:34data
- 9:34or collect the sample so that could be
- 9:36the reason you are emphasizing more on
- 9:38convenience sampling so and and some
- 9:41certain times
- 9:42when we go more into the depth of the
- 9:43judgmental sampling or the snowball
- 9:45sampling
- 9:46which is quite talking about
- 9:49cross layer model where the reference is
- 9:52going to play a very important role so
- 9:54that is the thing which is there so
- 9:55alternatively known as random sampling
- 9:57this is known as non random sampling
- 9:59and basis of selection is randomly that
- 10:00is very true and
- 10:02randomly you are going to select the
- 10:04content or you know the sample from pro
- 10:07if you're talking about the probability
- 10:08sampling but if you are talking about
- 10:10non-random probability sampling or non
- 10:11random sampling you are arbitrarily
- 10:13taking the
- 10:14sample so opportunity of selection is
- 10:16fixed and known that is very true and
- 10:18not specified in unknown
- 10:20so research is conclusive it's very true
- 10:22and end of the result what you are going
- 10:23to get
- 10:24you are going to get a very conclusive
- 10:25result which is which is quite holistic
- 10:27in nature whereas
- 10:28whereas when you are talking about
- 10:30non-probability sampling it is quite
- 10:31exploratory
- 10:32we will see there are certain methods
- 10:34like snowball
- 10:35uh nonven sampling methods which
- 10:39which purely based on the reference like
- 10:41we will send
- 10:42the questionnaire to respondents and ask
- 10:45the respondents to
- 10:46provide a certain you know the lead and
- 10:48on the basis of that lead we can again
- 10:50you know
- 10:51hit that particular respondents and ask
- 10:53certain questions from them so this
- 10:55could be the modus operandi
- 10:56which talks about that how the
- 10:58exploratory studies there and these are
- 10:59quite consuming you know
- 11:01and it's quite holistic in nature and
- 11:03and takes into consideration you know
- 11:05the time factor and other things so
- 11:07results are unbiased
- 11:08and results are biased because you are
- 11:11quite
- 11:11the example which i have quoted about
- 11:13you know the convenience sampling that
- 11:14you are
- 11:15for your convenience you are going and
- 11:17and choosing the particular judicials
- 11:19and you know that if you go for other
- 11:21jurisdictions maybe some different
- 11:22results will come but
- 11:23it's really cumbersome for you to you
- 11:25know collect the data from different
- 11:26states so since you have
- 11:28confined yourself to the particular
- 11:31judicion i think you are quite biased in
- 11:33that manner so
- 11:34this is the model which is there and
- 11:37methods are objective
- 11:39that is very true you are quite object
- 11:41oriented whereas
- 11:42methods are subject-oriented and you
- 11:44could be quite subjective
- 11:46and as far as the inferential inferences
- 11:49is concerned as far as
- 11:50you know the thing is concerned this
- 11:53probability sampling talks about the
- 11:54statistical way of doing the things and
- 11:57non-probability sampling talks about the
- 11:59analytical way of doing that thing so
- 12:01here you know the hypothesis is need to
- 12:03be tested when you are going to talk
- 12:04about the probability sampling
- 12:05whereas here the hypothesis need to be
- 12:07generated so sometimes what happen
- 12:09uh when you are you know uh applying the
- 12:12non-probability sampling
- 12:13you get certain hypotheses which need to
- 12:15be generated or it could not be
- 12:18it could not be an alternative
- 12:19hypothesis but it can be a new kind of
- 12:21hypothesis which can again added in this
- 12:23list of hypotheses so
- 12:26the impact of these kind of
- 12:28non-probability sampling is that
- 12:30somewhere after certain time what you
- 12:32observe that that
- 12:34that your research could be lingered
- 12:36down some in some of the cases so anyway
- 12:38we have very very elaborately compared
- 12:41the term called
- 12:42this particular thing so non-probability
- 12:44or non-random sampling is a process of
- 12:46selecting sampling from a population
- 12:48without using statistical probability
- 12:50theory and
- 12:52if you talk about you know the
- 12:53non-probability sampling theory each
- 12:55element of member of the population does
- 12:56not have an equal chance
- 12:58of being included in the sample and the
- 12:59researchers cannot estimate the error
- 13:01cost by not collecting data
- 13:03from all elements member of the
- 13:05population so that is where which is
- 13:06which is there and if you go more into
- 13:08the depth of this non-probability
- 13:10sampling i think
- 13:10it's quite purposive in nature and that
- 13:12has to do with sampling
- 13:14addressing the question for research and
- 13:16the research sample is qualitative type
- 13:18and the probability sampling focus on
- 13:21external value for transferring of
- 13:22issues
- 13:23and the very important thing is that the
- 13:26series and control of sample is
- 13:27non-probability random sampling
- 13:28typically
- 13:29smaller than 30 cases again so in every
- 13:32junction you will observe that you are
- 13:33quite biased and
- 13:34you are quite you know making the things
- 13:36as per your convenience as per your need
- 13:38so that that could be the reason you
- 13:40know the result which used to come
- 13:43it have a very short-sighted approach
- 13:45and not
- 13:46giving the very holistic view or the or
- 13:48the robust report so
- 13:49non probability sampling have numerous
- 13:51sample of size which is determined by
- 13:53the purpose of particular x
- 13:55component and and this is you know
- 13:59using more rigid side estimation
- 14:00procedures so when we are going to talk
- 14:02about you know the certain types of
- 14:04these judgmental convenience purposes or
- 14:06snowball
- 14:07or you know the quota sampling we will
- 14:09see that how this non-random sampling
- 14:12differs from from the random sampling
- 14:15and what are the usp behind that so the
- 14:17methods are non-probability random
- 14:18sampling use
- 14:19wide range of sampling techniques so the
- 14:21reason behind is quite clear that
- 14:24sometimes what happen we are not in a
- 14:25position to collect the data
- 14:27or not you know getting an opportunity
- 14:30that respondents are
- 14:31reciprocating to us in that manner so
- 14:34what exactly we are going to do
- 14:35we are applying the certain methods
- 14:38which are quite important so
- 14:39in general we have four important
- 14:42ingredients which are
- 14:43part of non-probability sampling that is
- 14:45convenient sampling judgmental sampling
- 14:47quota sampling and snowball sampling so
- 14:51ah if we if we start with you know the
- 14:53non-probability sampling
- 14:55i think that this convenience sampling
- 14:58is talks about in the members of
- 14:59populations which are selected that are
- 15:00easily available for study
- 15:02and if you talk about the quota sampling
- 15:03sample generated by dividing the
- 15:05population to separate groups
- 15:06and selective members from each group
- 15:08that is non-representative quota
- 15:10and like you know we have taken we are
- 15:12going to take a data off
- 15:13of the mail which is of 50 years or you
- 15:16know taking the
- 15:17data of females of of of between you
- 15:20know 24 to 30 years so
- 15:22we have restrict ourselves so that could
- 15:23be the model by which you know the quota
- 15:25sample used to work
- 15:26and when you are going to talk about the
- 15:27snowball sample this sample in which
- 15:29members of the sample select further
- 15:31members for inclusion in the sample so
- 15:32here what happened we first float the
- 15:34information
- 15:35float the questionnaire to respondents
- 15:38and then ask the respondents to give us
- 15:39certain
- 15:40references so this is this works with
- 15:43the
- 15:44in a model called multi-level marketing
- 15:46or network marketing or
- 15:47or you know the reference uh procedures
- 15:50where
- 15:51the if we interact with one person the
- 15:52other person can give the reference of
- 15:54three
- 15:54and this could be the model so while you
- 15:56know elaborately talking about this
- 15:57snowball sample we will
- 15:59very easily view that how the things are
- 16:01going to be changing self-selecting
- 16:02purposive sample is there which in which
- 16:04member of population
- 16:06select themselves for inclusion in the
- 16:07sample so anyway i think
- 16:10this is another difference which talks
- 16:12about
- 16:13that how the things are going to be
- 16:14changed and there are certain advantages
- 16:16there are certain
- 16:18cost and degree and there are certain
- 16:19disadvantages also so if you talk about
- 16:22convenience is very low cost
- 16:24extensively used if you talk about
- 16:26judgment
- 16:27it's moderate cost average use and if
- 16:29you talk about quota moderate
- 16:30cost very extra extensively use and low
- 16:33cost use in special situation that for
- 16:35the snowball
- 16:36model is concerned so we start with the
- 16:38purpose of sampling
- 16:39and we will cover you know all the five
- 16:41heads which comes under the ambit of
- 16:44methods of sampling as far as the non
- 16:45random sampling is concerned we see that
- 16:47this purpose is sampling is quite biased
- 16:49in nature and
- 16:51from the very beginning you know you
- 16:52observe that that deliberately
- 16:54the person which had been taken
- 16:56extracted or you know the sample which
- 16:58need to be taken is quite biased so
- 17:00this is called purposive sampling we
- 17:01have we have populations and purposes of
- 17:03sampling is
- 17:04that we are biased that we are going to
- 17:06take only you know the black color
- 17:08uh person as a sample so we have taken
- 17:10only that only so this is the model
- 17:12which is there if you talk about
- 17:13snowball sampling this is a chain
- 17:15referral sampling and
- 17:16if you see this chain reference sampling
- 17:18this this chain referrals
- 17:20works in the manner which i am talking
- 17:22about that the multi-level marketing or
- 17:23the
- 17:23network marketing where the chain is
- 17:25there so while you know
- 17:27floating the sample to one person now we
- 17:30have taken a reference of
- 17:32two person from this person and these
- 17:34two person had given a difference of
- 17:36three more so one person had given a
- 17:37reference of three other had given a
- 17:39reference of three
- 17:40now from that three we have got you know
- 17:42the huge number of samples
- 17:44so these are considered to be a mouth
- 17:46marketing model or you know the way
- 17:48where we have we have seen and how the
- 17:50things are going to be
- 17:51moved and snowball sampling or chain
- 17:54reference sampling is defined as a non
- 17:55probability sampling techniques
- 17:57and which have crates that are rare to
- 17:59find and
- 18:00the this sample technique in which
- 18:02existing subjects provide refers to
- 18:04recruit samples
- 18:05so and this is sometimes you know quite
- 18:08important and this sampling method
- 18:09involves a primary data source
- 18:11nominating other potential data source
- 18:13so what exactly we are doing that when
- 18:15we formulate objectives when we
- 18:16on the basis objective we frame the
- 18:18hypothesis and on the basis of
- 18:20you know this hypothesis we
- 18:24frame the questionnaires and then these
- 18:26questionnaires are sent to the
- 18:27respondents
- 18:28and once the respondents reciprocates
- 18:31then what
- 18:32exactly we are going to do we can
- 18:35know we can very easily know that that
- 18:37you know the
- 18:38reciprocation is very less the
- 18:40respondents are not reciprocating
- 18:42the manner they're supposed to do so
- 18:44what exactly we are
- 18:46going to do in that case we take a
- 18:47reference from from these
- 18:49you know the the respondents that why
- 18:51not you can give us some more reference
- 18:53so
- 18:53and this nominating other potential data
- 18:55source is there and
- 18:56and this snowball sampling method is
- 18:58purely based on reference
- 19:00that is very true and uh it either it
- 19:02could be and these referrals are are you
- 19:04know
- 19:05uh are coming in due course of you know
- 19:07the collection of primary data it's not
- 19:08like that
- 19:09that you're going to collect the data so
- 19:11the the respondents the the bona fide
- 19:13respondents to whom you have floated the
- 19:15questionnaires
- 19:16they can give the the the references
- 19:19or they can give the referrals so these
- 19:20referrals are are you know
- 19:22and when the when you are making a
- 19:24question here you should you know design
- 19:25a question in such a manner
- 19:27that in this this particular question
- 19:28here you are going to ask
- 19:30you know the referrals so this snowball
- 19:33sampling is a popular business study
- 19:34method
- 19:35and which is which is going on the way
- 19:37things are going to be done because
- 19:38the way e-commerce companies are going
- 19:40to do the research or
- 19:42you know the the other
- 19:45way of research is coming out we have
- 19:48observed that this snowball sampling
- 19:49method extensively used where population
- 19:51is unknown and rare and it is tough to
- 19:53choose subject to assemble them as a
- 19:54sample for research so
- 19:56then we have observed that this
- 19:57convenience sampling is
- 19:59is is a very is a different method which
- 20:01talks about collection
- 20:02collecting data quickly and fewer rules
- 20:06to follow
- 20:07and this is again you know inexpensive
- 20:09methodology
- 20:10and easy to do research and this if you
- 20:13talk about the strength and weakness
- 20:15because when we are going to do the
- 20:16sampling
- 20:17we always do the swot analysis that that
- 20:18is strength weakness opportunity and
- 20:20threat
- 20:21and when we check these two parameters i
- 20:23think strength
- 20:24this is low cost time and administration
- 20:26high participation and generalization
- 20:27because
- 20:28uh because you know as far as the
- 20:30convenience sampling is concerned it's
- 20:31quite convenient you
- 20:32you can define the jourdains you can
- 20:34define your population and sometimes you
- 20:36can define your sample also
- 20:38so what exactly we um what what exactly
- 20:40we mean to say
- 20:41if you talk about the weakness it's
- 20:43generalizing subjects id population
- 20:45results depend on the characteristics of
- 20:47sample so
- 20:49this convenience sampling is defined as
- 20:50a method adopted by researchers
- 20:52where they collect market research data
- 20:54from a conveniently available pool of
- 20:56respondents so
- 20:57you have got a pool of respondents and
- 20:59you can very easily you know
- 21:01as per your convenience as per your you
- 21:02know pace you can collect the data
- 21:04so it is most common use sampling
- 21:06techniques as it is incredible prompt
- 21:08uncomplicated and economical so
- 21:10researchers use convenience sampling in
- 21:12situations where additional inputs are
- 21:13not necessary for the principal research
- 21:15and the components of the population are
- 21:17eligible and dependent on the
- 21:18researchers proximity to get involved in
- 21:20the sample so we have seen that
- 21:22that as far as the convenience sampling
- 21:24is concerned we have seen that how the
- 21:25researcher had
- 21:26had taken no purple figures in the
- 21:29sample so he had just taken you know
- 21:31only the sample
- 21:32which is which is away from the purple
- 21:34colors
- 21:35so this is a convenient sampling so
- 21:36again what i mean to say when you are
- 21:38going to talk about the non-random
- 21:39sampling it is quite biased in nature
- 21:41because this is you know somewhat
- 21:44talking about
- 21:44the convenience so select any member of
- 21:46the population work conveniently and
- 21:48readily available
- 21:49and then there are certain applications
- 21:51of convenience sampling so convenience
- 21:52sampling is applied
- 21:53by brands and organization to measure
- 21:55their perception of the image in the
- 21:57market
- 21:58that is very true because they can they
- 22:00can know about you know the brand
- 22:01loyalty they can know about the usage or
- 22:03the behavior of the consumers
- 22:05vis-a-vis to particular product so data
- 22:07is collected from potential customers to
- 22:08understand
- 22:09specific issues so there is always a
- 22:12chance that randomly selected population
- 22:14may not accurately represent the
- 22:15population of interest
- 22:17thus increasing the chance of bias so so
- 22:19anyway i think
- 22:21if you talk about you know the
- 22:22judgmental sampling which is again you
- 22:24know the
- 22:25the fourth ingredient of of this
- 22:26particular methods of sampling
- 22:29which we usually call non-random
- 22:31sampling i think this consumes minimum
- 22:33time for execution
- 22:35and directly approachable to respondents
- 22:37because
- 22:38and almost real time results are coming
- 22:40up so
- 22:41that is the reason you know you observe
- 22:42that when any e-commerce company sold
- 22:44the product
- 22:45they just put the budge on there on
- 22:47their portal and the
- 22:49the moment this consumers log in the
- 22:52particular portal
- 22:54or do the e-commerce the it asks for you
- 22:56know what your experience related to the
- 22:57particular
- 22:58product which you have ordered you know
- 23:00or two days back so
- 23:02in that case what we observe that this
- 23:03is considered to be a
- 23:05going to give the real time results and
- 23:07easy to conduct it quite easy to conduct
- 23:09because
- 23:10uh because the moment consumer login i
- 23:12think the first
- 23:13you know the budge or the question comes
- 23:15uh from the e-commerce portal to the
- 23:17consumers that
- 23:18that how you are going to how what do
- 23:19you think about the product and
- 23:21how we can you know enhance our services
- 23:24or other models so
- 23:25this is the thing which is there's
- 23:26another form of convenience sampling
- 23:27where participants are handpicked
- 23:29from the accessible population
- 23:31researchers select participants that are
- 23:33representative of the entire population
- 23:35and very subjective sample method can be
- 23:37biased so judgmental sampling is a form
- 23:39of convenience sampling or we can say in
- 23:40which the population elements are
- 23:42selected
- 23:42and based on the judgment of the
- 23:44researchers so sometimes again you know
- 23:47this is quite biased and when you are
- 23:49going to compare with the random
- 23:50sampling because
- 23:51the in this case also they as far as the
- 23:54final
- 23:54opinion is going to be considered the
- 23:56researcher role is very important and he
- 23:58is going to
- 23:58do the sampling as per the up its
- 24:01convenience and as per his judgment
- 24:03so test markets purchase engineers
- 24:04selected industrial market research
- 24:06expert witness used in court so these
- 24:09are considered to be the judgmental
- 24:10sampling and then you have
- 24:12got a quota sampling so if you talk
- 24:13about you know the quota sampling
- 24:15this it had also certain strength and
- 24:18weakness
- 24:18and its low cost time and administration
- 24:22is involved high participation in
- 24:24generalization that is very true
- 24:25and more representative of individual
- 24:27population the example which i have
- 24:28quoted about
- 24:29you know choosing you know the teenagers
- 24:32who are who are you know between in the
- 24:34bracket of
- 24:3515 to 18 years or if you talk about
- 24:38weakness generalizing subjects id
- 24:40population results depend on
- 24:41characteristic
- 24:42sample more time consuming so one one
- 24:45type of this is
- 24:46another type of non-probability sampling
- 24:47and must begin with the matrix of target
- 24:49population characteristic that is
- 24:51percentage males percentage females uh
- 24:54ses etc
- 24:55the set quota percentage of each
- 24:57character is fulfilled in the
- 24:58sample so there are certain advantages
- 25:01again because quota sampling means to
- 25:02take a very tailored sample
- 25:04and easy to administer fast to create
- 25:07and complete
- 25:08inexpensive and takes into account
- 25:10population proportions if desired
- 25:12and can be used if probability sampling
- 25:14techniques are not possible
- 25:16so what we observe that sometimes what
- 25:18happens there are certain probability
- 25:19sampling
- 25:20which which is not you know applicable
- 25:22so in that case you know the quota
- 25:23sampling is going to be done
- 25:25so this quota sampling is
- 25:28taken massively by by the by the
- 25:30governments and selection is not random
- 25:32selection
- 25:33bias poses a problem for example you
- 25:34might avoid choosing people
- 25:36who live farther away or people in rough
- 25:37neighborhoods this may take the results
- 25:39unrepresentative of the
- 25:41population so this is a this is a model
- 25:43of quota sampling where you have seen
- 25:44that
- 25:45from this particular group from this
- 25:46particular uh thing
- 25:48you know the the male population had
- 25:51been
- 25:52taken and who are in the bracket of 50
- 25:55years so
- 25:56anyway i think i have talked a lot about
- 25:59this random sampling i have talked a lot
- 26:02about
- 26:03this non-random sampling and this and
- 26:06i have very you know very ah
- 26:09meticulously
- 26:11explained in the very beginning that
- 26:12sampling is a technique you know
- 26:14and it's not like that you can you can
- 26:16just you know uh
- 26:18consider the population or you know
- 26:20earmark the population or universal then
- 26:23just extract the data from that
- 26:24particular population there must be
- 26:26certain modus operandi
- 26:27there must be certain procedures there
- 26:29must be certain methods
- 26:30and when you are going to talk about the
- 26:32methods i think you have to
- 26:34first see what exactly the sampling is
- 26:36and how you're going to collect the
- 26:37sample and what could be the modus
- 26:39operandi you are going to do
- 26:40and what are the ways you are going to
- 26:41apply like you know the non-random
- 26:43sampling you are going to applying or
- 26:45you are going to apply the
- 26:47the probability sampling but you have to
- 26:50see you know what exactly the demand
- 26:52comes from as far as the researcher is
- 26:54concerned
- 26:55so the certain time you know what we
- 26:57observe that when we are doing our
- 26:59research i think
- 26:59and we have taken a population or the
- 27:02universal or we have earmarked the
- 27:04population we just to narrow down the
- 27:07research just to
- 27:08you know cut short the research or try
- 27:11to
- 27:11condense the research in a in a shorter
- 27:14span
- 27:15we try to follow a fast track mode or
- 27:17you know the shortcut methods
- 27:19which is which is no way permissible as
- 27:22far as the research is concerned so
- 27:23being a researcher
- 27:24you have to be quite elaborative you
- 27:26have to have a patience and you have to
- 27:28see that how you're going to do the
- 27:29sampling
- 27:30because the whole genesis behind the
- 27:32good research is the sample because
- 27:34the population is something which you
- 27:35have earmarked or the universal which
- 27:37you have
- 27:38explored this is something which can
- 27:40give you the boundary
- 27:41but when you are when you are going to
- 27:43play in that in that ground or in the
- 27:45boundary i think
- 27:46there you have to see because when you
- 27:49enter into the
- 27:50into the playground you have to very
- 27:52easily make up your mind that you're
- 27:53going to play cricket today you're going
- 27:55to play football or you're going to play
- 27:56other games
- 27:58if you know the intention is not clear
- 28:01in your mind that what exactly you're
- 28:02going to
- 28:03play i think somewhere you are confused
- 28:05so and uh
- 28:06it's and that that confusion is going to
- 28:09eradicate once you
- 28:10once you know about you know the basic
- 28:12phenomena of
- 28:13of the sampling or you know the methods
- 28:16of sampling
- 28:17these sampling techniques are are you
- 28:20know quite vibrant in nature and
- 28:21it is not like that that one sample you
- 28:24have used and you are rigid to that
- 28:26so sometimes what happens we start with
- 28:27the random sampling
- 28:29that is stratified sampling simple uh
- 28:31random sampling or you know
- 28:33the systematic sampling or you know the
- 28:35other way of doing the things
- 28:37but after certain time we realize that
- 28:39that
- 28:40that the data is not coming in the
- 28:41manner we have we have presumers
- 28:44are supposed to be do so in that case
- 28:46what exactly you have to do you have to
- 28:48work as a juggler which i have told in
- 28:49the in my preceding session also that
- 28:52you have to do the thing in such a
- 28:54manner that you can jump to the other
- 28:56modes of doing the things so if you have
- 29:00started the journey with
- 29:01with convenience sampling or the cluster
- 29:03sampling or the stratified sampling
- 29:04so because these these are the way by
- 29:07which you can
- 29:08able to interpret the particular
- 29:10clusters or if you talk about
- 29:12the stratifieds random sampling you can
- 29:14make certain groups and do the things
- 29:15but
- 29:16when you move from this convenience
- 29:17sampling to judgmental sampling some way
- 29:19it also helps
- 29:20because it can give you an uh different
- 29:22way of doing the things
- 29:23and on the other hand what we observe
- 29:25that you have started with the random
- 29:27sampling then you have
- 29:28moved to the non random sampling and
- 29:30apply the snowball sampling now the
- 29:32snowball sampling
- 29:33is purely working on the on the
- 29:34references or to the chain model
- 29:36so if you if you interact with few
- 29:39respondents and you ask these
- 29:41respondents to give
- 29:42the you know the details about the other
- 29:45respondents where you can float your
- 29:46questionnaire i think
- 29:47this is one of the way by which you know
- 29:49you can you can get your access more and
- 29:51and these these respondents considered
- 29:53to be the potential respondents
- 29:55it's not like that you can you can
- 30:00just moving isolately or or
- 30:04exploding the things in a in a dark room
- 30:06you are
- 30:07quite knowing that that you are going to
- 30:08do the things or you are just you know
- 30:11going to the right researchers or right
- 30:12respondents so i think
- 30:14this is the beauty of the sampling and
- 30:17and we
- 30:17we know that when we when we start the
- 30:19sampling when we do the sampling when we
- 30:21apply certain techniques or methodology
- 30:23certain errors comes in between and
- 30:25these errors work as a alarm
- 30:27alarm bell and once you get the data and
- 30:31so the motors are printed like that once
- 30:33you have reciprocates once once you have
- 30:35started you know collecting the
- 30:37uh the data from the respondents in the
- 30:39primary mode
- 30:40you try to evaluate those data after
- 30:43it's not like that
- 30:44that you have you have a sample size of
- 30:47of 400 or 500 and 100 people have
- 30:49reciprocate then you wait for another
- 30:51400 and then come to the conclusion
- 30:53it's not like that you the the movement
- 30:55you know 100 people have reciprocates
- 30:57you make a small you know competitive
- 30:59view or
- 31:00of the of the respondents reports and
- 31:03try to find out
- 31:04that what exactly uh you know
- 31:07the things are coming out if you know
- 31:09the results considered to be
- 31:11appreciable or you know the considered
- 31:14results considered to be
- 31:17satisfactory then you can carry on with
- 31:19that otherwise in
- 31:20in between you have to apply certain
- 31:22other methodologies which can give you a
- 31:24model which can give you a platform
- 31:26that that you reach to a a conclusion so
- 31:30i think this could be the way and we
- 31:32have to be quite
- 31:33quite serious when we are doing
- 31:37when we are in the process of collecting
- 31:38a sample because the if you have
- 31:39collected the sample of 100 respondents
- 31:42and
- 31:42and if you have made the competitive
- 31:43view i think the interpretation could be
- 31:46quite clear that whether you are moving
- 31:47a right direction
- 31:48or you know some some other points need
- 31:51to be added in questionnaire which can
- 31:52give you a more
- 31:53more elaborative result so that is where
- 31:55you know you have to stop yourself
- 31:57or you have to revamp your questionnaire
- 31:59and then you have to start your journey
- 32:01so
- 32:01so i think this this research when we
- 32:04talk about the research when you talk
- 32:05about the research plan
- 32:06when we talk about the research design
- 32:08it's not like that you have make the
- 32:10research plan or design the very
- 32:11beginning
- 32:11you have to be quite you know agile or
- 32:14or you know
- 32:16be active as far as the research process
- 32:18is going on so
- 32:19every juncture you have to recapitulate
- 32:21yourself you have to
- 32:22see whether you are moving in a right
- 32:24manner or or you know
- 32:26what certain things would need to be
- 32:27added or deleted or
- 32:29you know subtracted so that you can
- 32:31after certain time you read you need
- 32:34lead to a final conclusion so anyway i
- 32:36think we are going to
- 32:38wind up this particular session which is
- 32:39quite thought provoking and very
- 32:41important as far as the
- 32:42as far as the researcher is concerned
- 32:44because sampling is is very important
- 32:46ingredient
- 32:46you know and in the next session we are
- 32:49going to talk about the errors they are
- 32:50margin of errors there are
- 32:51statistical errors or sampling errors
- 32:54and how these sampling errors are
- 32:56are working as a alarm bell and how
- 32:59you're going to come out because if you
- 33:00are familiar with
- 33:01with the with the pros and cons i think
- 33:04the the result which you are used to get
- 33:05it's quite foolproof in nature
- 33:07so thank you learners we will have
- 33:09another sessions in coming days thank
- 33:11[Music]
- 33:22you
- 33:27you
About this transcript
This page contains the full transcript of Non Random Sampling by MCO-3 [RM&SA], generated from the public captions YouTube serves with the video. The transcript has 6,454 words across 1,133 segments, with the original timestamps preserved so you can click any line to jump to that moment in the embedded player.
What you can do with it
Use the transcript to take notes, quote the speaker, build a study guide, generate a summary with ChatGPT or Claude via the YouTube Summary tool, or export it as a timed subtitle file with YouTube to SRT. You can also re-open it in the transcriber to translate the transcript into 100+ languages.
Free YouTube transcript tool
YouTube2Text is a free YouTube transcript generator — no signup, no daily limit. Paste any YouTube link and get the full transcript instantly, with timestamps, click-to-jump, translation to 100+ languages, AI prompts for ChatGPT, Claude, and Gemini, and exports to TXT, SRT, VTT, or Markdown.