YouTube2Text

YouTube transcript (UrRYITjDOww) — Transcript

5,618 words · 762 segments · language en · Watch on YouTube

Full transcript

  1. 0:02[Music]
  2. 0:17hello thanks for watching and welcome to
  3. 0:20the next video in my series on basic
  4. 0:22statistics now as usual a few things
  5. 0:25before we get started number one if
  6. 0:27you're watching this video because you
  7. 0:28are struggling in a class right now I
  8. 0:31want you to stay positive and keep your
  9. 0:33head up if you're watching this it means
  10. 0:35you've accomplished quite a bit already
  11. 0:37you're very smart and talented but you
  12. 0:39may have just hit a temporary rough
  13. 0:41patch now I know with the right amount
  14. 0:43of hard work practice and patience you
  15. 0:46can work through it I have faith in you
  16. 0:49many other people around you have faith
  17. 0:51in you so so should you number two
  18. 0:55please feel free to follow me here on
  19. 0:57YouTube on Twitter on Google+ or on
  20. 1:01LinkedIn that way when I upload a new
  21. 1:03video you know about it and it's always
  22. 1:06nice to connect with my viewers online
  23. 1:08I'll feel that life is much too short
  24. 1:10and the world is much too large for us
  25. 1:12to miss the chance to connect when we
  26. 1:14can number three if you like the video
  27. 1:17please give it a thumbs up share it with
  28. 1:20classmates or colleagues or put it on a
  29. 1:22playlist that does encourage me to keep
  30. 1:24making them for you on the flip side if
  31. 1:27you think there's something I can do
  32. 1:28better please leave a con instructive
  33. 1:30comment below the video and I will take
  34. 1:32those ideas into account when I make new
  35. 1:35ones and finally just keep in mind that
  36. 1:37these videos are meant for individuals
  37. 1:39who are relatively new to Stats so I'm
  38. 1:42just going over basic concepts and I
  39. 1:45will be doing so in a slow deliberate
  40. 1:48manner not only do I want you to know
  41. 1:51what is going on but also why and how to
  42. 1:55apply it so all that being said let's go
  43. 1:58ahead and get started so this video is
  44. 2:01part two of our larger video on the
  45. 2:04one-way analysis of variance or the
  46. 2:06oneway Innova now in part one we went
  47. 2:10over an example problem and really sort
  48. 2:12of took it apart and looked at how all
  49. 2:14the parts of the oneway and Nova fit
  50. 2:17together so in part two we're going to
  51. 2:20go into Microsoft Excel and do a quote
  52. 2:23hand calculation of the oneway Anova so
  53. 2:27if you're watching the video on YouTube
  54. 2:29you can go to the description deson
  55. 2:30below the video and there you'll find a
  56. 2:32link to the corresponding blog post for
  57. 2:35this problem on the blog post you can
  58. 2:37actually download a blank version of the
  59. 2:39Excel file we're going to use and you
  60. 2:41can follow along step by step so without
  61. 2:44further waiting let's go ahead and get
  62. 2:46started on part two of the one-way
  63. 2:49analysis of
  64. 2:51variance now what we're going to do in
  65. 2:54Excel is try to replicate the output in
  66. 2:58SPSS and again SPSS is the statistical
  67. 3:02software I use in my work so I went
  68. 3:04ahead and did our example problem in
  69. 3:07SPSS and this was the result so we're
  70. 3:10going to go into Excel and actually try
  71. 3:11to replicate this Anova chart doing hand
  72. 3:15calculations and of course I don't mean
  73. 3:17literally by hand we're going to use
  74. 3:19Excel formulas but in the end we want to
  75. 3:22have a chart that looks exactly like
  76. 3:26this now before we actually go into
  77. 3:28Excel we do have to go over a few
  78. 3:31formulas for the oneway Inova now I
  79. 3:34mentioned before that some textbooks and
  80. 3:36some professors and classes and
  81. 3:39everything else call the same things by
  82. 3:42different names so you may have to cross
  83. 3:45reference what we're going to learn here
  84. 3:46with how it's presented in your class so
  85. 3:49you may actually want to have your
  86. 3:50textbook open or your notes open as we
  87. 3:53go through it it's the same thing but
  88. 3:55again they go by different names
  89. 3:57depending on what text you're using or
  90. 3:58what Professor you have
  91. 4:01so before we do that I just want to
  92. 4:02point out what's going to come up um
  93. 4:04here in a second when you see the
  94. 4:06variable in or the large n that
  95. 4:09represents the total number of
  96. 4:11observations in our experiment or in our
  97. 4:14problem in this case it's 21 remember
  98. 4:18now C is the number of columns we have
  99. 4:22in our chart remember in this problem we
  100. 4:24had three because we had three years of
  101. 4:28students so let's talk about SSC
  102. 4:31remember that's sum of squares of the
  103. 4:33columns or sometimes What's called the
  104. 4:35treatments it's also the levels of our
  105. 4:38single Factor we're looking at remember
  106. 4:41I said they can go by different names
  107. 4:42that's what I mean so in this case we
  108. 4:44had year one year 2 and year three those
  109. 4:47are our
  110. 4:49columns now the SSC also has a degrees
  111. 4:52of freedom actually all these have their
  112. 4:54own degrees of freedom in the SSC case
  113. 4:58the degrees of freedom of the columns is
  114. 5:02C
  115. 5:04minus1 now the
  116. 5:06MSC is the mean squared of the columns
  117. 5:11so mean square of the columns that's
  118. 5:15MSC and that is the SSC so the sum of
  119. 5:18squares of the columns divided by its
  120. 5:21own degrees of freedom again this is all
  121. 5:25very abstract until we do it so just
  122. 5:27hang with me so the SS e is the sum of
  123. 5:31the squares of the error or the within
  124. 5:34each column each individual column sum
  125. 5:37of squares so the SSC is a sum of
  126. 5:40squares between the columns the SS is a
  127. 5:43sum of squares within each
  128. 5:46column so degrees of freedom for SSC is
  129. 5:50n minus C and again we'll put numbers in
  130. 5:54all these here in a minute so the MSE is
  131. 5:58the mean squared error now the MSE is
  132. 6:02very important in many areas of
  133. 6:04Statistics so keep that in the back of
  134. 6:06your head as we proceed but msse is the
  135. 6:09mean squared of the error and that is
  136. 6:12the ssse divided by the degrees of
  137. 6:16freedom for the
  138. 6:17error and then we have SST which of
  139. 6:21course is the sum of squares of the
  140. 6:22total the total sum of squares the
  141. 6:25degrees of freedom for the SST is in -1
  142. 6:30so the total number of observations
  143. 6:34minus1 now in the end we will end up
  144. 6:37with an F statistic remember way back
  145. 6:40when in our f-stat video what the f
  146. 6:42statistic is it's a ratio the F ratio is
  147. 6:47a ratio of two variances so in our F
  148. 6:51ratio here in the numerator we're going
  149. 6:54to have the mean sum of squares for the
  150. 6:57columns which is the variant
  151. 7:00between the
  152. 7:01columns and then in the denominator
  153. 7:04we're going to have the mean squared
  154. 7:07error which is the variance of the sum
  155. 7:09of squares inside the columns so we have
  156. 7:13between the columns on top and within
  157. 7:17the columns in the denominator that's
  158. 7:19why you will often see this as an F
  159. 7:22ratio that is between divided by Within
  160. 7:27between the columns divided by the Vari
  161. 7:30of the data within the
  162. 7:34columns so let's go ahead and actually
  163. 7:36put some numbers in here let's find our
  164. 7:38degrees of freedom first so remember the
  165. 7:40degrees of freedom for SSC was C the
  166. 7:43number of columns minus one so in this
  167. 7:46case it's three because we have three
  168. 7:47columns minus one which equals 2 so the
  169. 7:52MSC equals the SSC divided by that
  170. 7:56degrees of freedom which is of course
  171. 7:58two
  172. 8:00now for the
  173. 8:01SSE the degrees of freedom for the ssse
  174. 8:04was n minus C so n is 21 that's number
  175. 8:09of overall observations minus 3 which is
  176. 8:12the number of columns so that is 18 so
  177. 8:16our msse equals the ssse divided by that
  178. 8:20degrees of freedom which is
  179. 8:2318 now the degrees of freedom total the
  180. 8:26SST is n minus one so our overall all
  181. 8:30number of observations minus 1 which of
  182. 8:32course is 21 - 1 = 20 now our F ratio
  183. 8:38Remains the Same it is still the msse
  184. 8:41divided by the
  185. 8:43MSE now let's go ahead and go into Excel
  186. 8:46and figure out the SSC and the SS which
  187. 8:51will allow us to find the MSC in the MSE
  188. 8:55that we need to do this
  189. 8:57problem so here we are in in Excel where
  190. 9:00we're going to do our hand calculation
  191. 9:02of this Anova problem but before I give
  192. 9:04you a tour of our spreadsheet here I
  193. 9:06want to draw your attention to the
  194. 9:07yellow box up here at the top now
  195. 9:10remember we're going to need the sum of
  196. 9:12squares however Excel does not have a
  197. 9:14sum of squares formula so what we're
  198. 9:17going to do is we're going to use the
  199. 9:18variance formulas and then alter them a
  200. 9:21bit so the Excel variance formulas which
  201. 9:23is var. S and var. P which is sample
  202. 9:28variance and population variance do the
  203. 9:30averaging step we don't want so the
  204. 9:33sample variance will divide by n minus
  205. 9:35one and the population variance will
  206. 9:37divide by n therefore we will have to
  207. 9:40sort of quote undo that step and make a
  208. 9:44couple of other adjustments to get the
  209. 9:45sum of squares we want so in the
  210. 9:48calculations we do in the formulas we
  211. 9:50use you will see multiplication added in
  212. 9:54that is the undoing of the variance
  213. 9:58averaging and other multiplication
  214. 10:00that's in the SST the SSC and the SS e
  215. 10:05so what I'm saying here is that some of
  216. 10:08this you're just going to have to take
  217. 10:10on faith and I hate saying something
  218. 10:12like that in a math video but that's
  219. 10:14just the way it is I did not go over the
  220. 10:17individual SST SSC and ssse formulas
  221. 10:21because I thought your face would glaze
  222. 10:23over anymore than it already is and you
  223. 10:25can find those in your books however I
  224. 10:28will try to point out out what each
  225. 10:30component is when we put in the formulas
  226. 10:33okay so that's sort of my little caveat
  227. 10:35here now on the top left you will see
  228. 10:37our chart our data as we had it in the
  229. 10:39PowerPoint portion so we have our year
  230. 10:41one scores our year 2 scores and our
  231. 10:44year three scores nothing much surprise
  232. 10:47there and then we have a column summary
  233. 10:50so the mean for year 1 year 2 and year
  234. 10:53three and then we have the overall mean
  235. 10:55there in the middle now over on the
  236. 10:58right hand side I just put the formulas
  237. 11:00for the sample variance and the sum of
  238. 11:02squares we're going to be doing if
  239. 11:04you're really not interested in the
  240. 11:05formulas that much just ignore those two
  241. 11:08blue boxes up there in the right hand
  242. 11:11side now if you look below our data
  243. 11:13you'll see n and C well n remember is
  244. 11:16going to be the total number of
  245. 11:17observations we have which in this
  246. 11:19problem of course will be 21 C is the
  247. 11:22number of groups or columns or
  248. 11:24treatments we have so in this problem
  249. 11:27will be three over on the right you will
  250. 11:30see the SPSS output for this problem so
  251. 11:34what we're going to try to do is
  252. 11:35replicate that little chart over there
  253. 11:38on the left hand side where we have the
  254. 11:40green header and then the SSC SSC SST
  255. 11:43there in that chart so we're going to
  256. 11:45try to make that chart on the left look
  257. 11:48like the SPSS output over here on the
  258. 11:51right and of course we will actually do
  259. 11:53this problem in Excel using its Anova so
  260. 11:56we're going to have three versions or
  261. 11:58three out puts of the exact same thing
  262. 12:01to make them all match now everything
  263. 12:03else on here is pretty much a hint so we
  264. 12:05don't have to go back to PowerPoint to
  265. 12:07find these formulas So Below there on
  266. 12:10the left hand side you will see the MSC
  267. 12:13the msse and the F ratio and again those
  268. 12:17just come from our slides we already had
  269. 12:20now in the purple boxes on the lower
  270. 12:22right those the formulas we're going to
  271. 12:24use to actually find our sum of squares
  272. 12:27so I will explain those further when we
  273. 12:29get to that step but I just wanted to
  274. 12:31put them here sort of in a text format
  275. 12:33so you can copy and paste them into the
  276. 12:36proper cell so let's go ahead and do
  277. 12:39some actual calculations and put in some
  278. 12:41data so the first thing we're going to
  279. 12:43do is we're going to go over to the n
  280. 12:45and the c boxes over here on the left
  281. 12:48hand side so this is easy so our n in
  282. 12:51this case is 21 so we're going to go
  283. 12:53ahead and put 21
  284. 12:54there that's the number of observations
  285. 12:57we have and then C is the number of col
  286. 12:59which is
  287. 13:00three so we'll go ahead and do that now
  288. 13:04the next thing I want to do is find the
  289. 13:07column means so we'll go up to the year
  290. 13:10one mean box which is the bottom of the
  291. 13:12year one scores and then we'll use the
  292. 13:15average formula so we'll type equals
  293. 13:19average and I'm actually go ahead and
  294. 13:21begin filling that out now we'll just
  295. 13:24select all seven of those scores in the
  296. 13:27year one column close print
  297. 13:29parentheses and there we go so this is
  298. 13:3371.7 which is what we had in the
  299. 13:35PowerPoint now we need the mean for all
  300. 13:38three columns so we'll go ahead and do
  301. 13:39the same thing for year
  302. 13:45two and we'll go and do the same thing
  303. 13:47for year three in case you're wondering
  304. 13:49I don't drag across because it takes the
  305. 13:50color with it so they would all be blue
  306. 13:52if I dragged across okay so we have the
  307. 13:56column mean for each of the student
  308. 13:59years so 71.7 one for year 1 students
  309. 14:0375.2 n for year 2 students and 7657 for
  310. 14:07year three students now we want the
  311. 14:10overall mean which is in this gray box
  312. 14:12here below the yellow box so again
  313. 14:15equals
  314. 14:17average and then we'll select all 21
  315. 14:22scores in our data and hit enter so now
  316. 14:26we have our overall mean of 7
  317. 14:314.52 so again using Excel we did hand
  318. 14:34calculations of all three column means
  319. 14:37and the overall mean which of course we
  320. 14:38know we need to do this type of problem
  321. 14:41now let's go ahead and go down to our
  322. 14:45chart over here on the lower left let's
  323. 14:47go ahead and find the degrees of freedom
  324. 14:50for each source of variance so remember
  325. 14:53we have column variance so between the
  326. 14:55columns we have within each column
  327. 14:57variance and then we have the the total
  328. 15:00sum of squares the total variance okay
  329. 15:02so remember that for the SSC we can see
  330. 15:05this sort of over here on the right hand
  331. 15:06side so degrees of freedom between which
  332. 15:09is the same thing as SSC is C minus one
  333. 15:13so we could say equals c which is this
  334. 15:16cell right here minus
  335. 15:19one and of course that is two now we
  336. 15:22need degrees of freedom for within so
  337. 15:25that is n minus C and you can see that
  338. 15:28little box on the right to help you sort
  339. 15:30of cheat a little so equals n which is
  340. 15:34that cell minus C which is that cell and
  341. 15:39that gives us 18 degrees of freedom now
  342. 15:41our total degrees of freedom is n minus
  343. 15:44one so this going to be equals in that
  344. 15:47cell minus
  345. 15:49one and that is 20 so that's very very
  346. 15:53easy now comes the hard part now we have
  347. 15:58to find the sum of
  348. 16:00squares now I went ahead and put
  349. 16:02placeholders in in our chart over here
  350. 16:04on the left hand side so we know where
  351. 16:06everything goes so you look in the SS
  352. 16:08column we have SSC SS and SST Su of
  353. 16:13squares column sum of squares erir and
  354. 16:15some of squares total now on the lower
  355. 16:18right you will see boxes outlined in
  356. 16:20sort of a purple color so those the
  357. 16:23actual formulas we're going to put in
  358. 16:26each one of those cells so let's take a
  359. 16:28look at each each one very briefly now
  360. 16:31there might be some multiplication in
  361. 16:32here you don't fully understand because
  362. 16:34I did not go over the actual formulas
  363. 16:37for SSC ssse and SST because they are
  364. 16:40mind- numbing you can find them in your
  365. 16:42book and the way we're doing it you
  366. 16:44really don't have to worry about it and
  367. 16:46that just sort of brings up my overall
  368. 16:48point the chances of you having to do an
  369. 16:50a Nova by hand are basically zero at
  370. 16:54least I hope not you're going to be
  371. 16:55using Excel or
  372. 16:57SPSS or many tab or whatever else it
  373. 17:00might be so we're doing all this by hand
  374. 17:02just so you can see how everything
  375. 17:03relates not because you'll have to do it
  376. 17:06that often and hopefully never so let's
  377. 17:08look at the top one first and that is
  378. 17:11SSC so in this one I'll go ahead and put
  379. 17:14my mouse in there you can see that we
  380. 17:16have SSC equals
  381. 17:20v.s that is the formula for sample
  382. 17:24variance and it's going to B sells A10
  383. 17:28to C10 let's go up here what is A10 and
  384. 17:32C10 well that is the column means so
  385. 17:37it's going to look at the variance of
  386. 17:39those three column
  387. 17:42means and then we multiply by two but
  388. 17:45where does the two come from in this
  389. 17:47case the two comes from the number of
  390. 17:48columns we have minus one so basically
  391. 17:52that's the same way of saying it's
  392. 17:53degrees of freedom so that's where that
  393. 17:55two comes from where does the seven come
  394. 17:57from well well that's how many
  395. 17:59observations we have in each column so
  396. 18:03v.s is the variance formula the sample
  397. 18:06variance formula for those three column
  398. 18:09means time 2 which is number of columns
  399. 18:12minus one so that's 2 time 7 which is
  400. 18:16the number of observations in each
  401. 18:19column so let's go ahead and go over
  402. 18:22here to our SSC box I'm going to take
  403. 18:24out the
  404. 18:25text then I'm going to go over here and
  405. 18:28copy
  406. 18:31our text in our box we'll go back over
  407. 18:33to the
  408. 18:34SS cell we'll paste it now I'm just
  409. 18:38going to take out the SSC part so delete
  410. 18:41delete delete hit
  411. 18:43enter and there we go so the sum of
  412. 18:46squares for the columns or the between
  413. 18:49sum of squares is
  414. 18:5188.6 67 repeating so let's go ahead and
  415. 18:55look at the SSE formula and it is
  416. 18:58admittedly much more involved if we take
  417. 19:00it apart we can see where everything
  418. 19:01comes from so we're using the v.s
  419. 19:04formula again so is the sample variance
  420. 19:08now the first one asks for cells A2
  421. 19:11through A8 well what are those well A2
  422. 19:15through
  423. 19:16A8 are the data points for column 1 or
  424. 19:21all the year one scores so we're asking
  425. 19:23for the sample variance of those seven
  426. 19:27scores
  427. 19:28now we're going to multiply by six well
  428. 19:31why are we multiplying by six well that
  429. 19:34goes up to the formulas up here at the
  430. 19:36top the sample variance is n minus one
  431. 19:38in the denominator well we do not want
  432. 19:40that we want to undo that so that's why
  433. 19:42we're multiplying by 7 - 1 which of
  434. 19:45course is six then we're going to add to
  435. 19:48that the variance of the next column so
  436. 19:51B2 through B8 same thing * 6 and then
  437. 19:55we're going to add that to the variance
  438. 19:584 three so C2 through C8 so that is all
  439. 20:02that is it's just the variance of each
  440. 20:05column added together so we'll go ahead
  441. 20:08and copy all that well first we'll go
  442. 20:11over to SSC and delete it make room now
  443. 20:14we'll go over copy all that contrl c on
  444. 20:18my PC contrl V to paste it now I'm going
  445. 20:22to go up and modify it by taking out the
  446. 20:25SS at the beginning delete now we hit
  447. 20:28enter
  448. 20:30and there we have a sum of squares
  449. 20:32within or an
  450. 20:34SS of 281
  451. 20:3712.57 so that is our sum of squares of
  452. 20:40the within and again that's within the
  453. 20:42columns we just add them all together
  454. 20:45now we'll go to SST sum of squares total
  455. 20:47so we'll delete
  456. 20:48that now if you look down here in our
  457. 20:51formula we have SS equal 20 * vs of A2
  458. 20:58through C8 well what is A2 through C8
  459. 21:02that's
  460. 21:03everything so A2 through C8 is our
  461. 21:07entire data set now we take the variance
  462. 21:10of that and we multiply it by 20 why
  463. 21:14well remember our variance is n minus
  464. 21:16one so we have 21 scores minus one we're
  465. 21:20going need to undo that put it in the
  466. 21:21top so that's what we multiply by 20 so
  467. 21:25we'll go ahead and select all
  468. 21:27that contrl C to copy we'll go over to
  469. 21:30our SS column here the SST contrl V to
  470. 21:34paste we'll take
  471. 21:36out the SST at the beginning hit enter
  472. 21:40and there we
  473. 21:41go now if you look close enough you will
  474. 21:43see that the
  475. 21:44SST is the sum of the SS and the SSC so
  476. 21:5188.6 667 plus 281 12.5 sish when you add
  477. 21:57those together you will get
  478. 22:0129123 so that goes back to the idea of
  479. 22:04partitioning the total variance so our
  480. 22:07total variance of SST is made up of two
  481. 22:09components the SS e and the SSC when you
  482. 22:13add those together you get the SST in
  483. 22:16return okay so a few more things to do
  484. 22:19now we need to find the
  485. 22:21MSC so that's up here under the MS
  486. 22:25column now if you look down here I have
  487. 22:27the little formula for the MSC or the
  488. 22:30mean square of the columns so we're
  489. 22:32going to delete the text and this is
  490. 22:34just the SSC divided by the degrees of
  491. 22:37freedom for columns and we have both of
  492. 22:39those so this is equal the SSC which we
  493. 22:43just found which is over here divided by
  494. 22:46the degrees of freedom for the SSC which
  495. 22:49is to the left of that so we go ahead
  496. 22:51and click that cell and hit enter now we
  497. 22:54have a mean Square for The Columns of 44
  498. 22:58. 3333 repeating now let's go ahead and
  499. 23:01do the
  500. 23:02msse so we'll delete the text in that
  501. 23:04cell so this is the SS divided by its
  502. 23:07degrees of freedom so we'll go to that
  503. 23:09cell we already have selected this is
  504. 23:12equal the SS the 281
  505. 23:1612.57 or whatever it was divided by its
  506. 23:20degrees of freedom which is to the left
  507. 23:21of it that's 18 and we'll go ahead and
  508. 23:24hit
  509. 23:25enter and that is 156
  510. 23:29257 so now we have our MSC and our MS e
  511. 23:36now what is f well f is merely division
  512. 23:40the MSC divided by the MSC of course we
  513. 23:42have both of those we just did them so
  514. 23:45the F here equals the
  515. 23:49MSC which is there to the left divided
  516. 23:52by the MSE e we found which is there hit
  517. 23:57enter and you'll notice we
  518. 24:00have 28 3726 Etc what was it in our SPS
  519. 24:05output look over here on the right our f
  520. 24:09is
  521. 24:11284 same thing so look at the SPSS
  522. 24:15output over here on the right and our
  523. 24:17chart we just did over here on the left
  524. 24:20what do you notice degrees of freedom
  525. 24:22for the between groups is two degrees of
  526. 24:25freedom for the within is 18 degrees of
  527. 24:27freedom to total is 20 the sum of
  528. 24:30squares for the between 88.6 67 it's in
  529. 24:34both the within sum of squares was 281
  530. 24:3812.57 same in both sum of squares total
  531. 24:432912 38 same in both so in Excel by hand
  532. 24:49we just replicated the output SPSS gave
  533. 24:52us so now you can see how everything
  534. 24:55works together now of course I do admit
  535. 24:58the only odd part of this are these
  536. 25:01formulas down here and again you're just
  537. 25:03going to have to look at them and figure
  538. 25:05out where everything is being uh pulled
  539. 25:08from but you're very smart and I know
  540. 25:09you can do that so let's do one more
  541. 25:12thing and let actually use excels built
  542. 25:14in an NOA to see if we get the same
  543. 25:18thing so we're going to go ahead and go
  544. 25:20up to data here at the top of the ribbon
  545. 25:24go all the way over to the right and
  546. 25:25you'll see data analysis so we'll click
  547. 25:28on that that now remember we are doing
  548. 25:31the Anova single Factor so we go and
  549. 25:34click
  550. 25:35okay now this wants the input range so
  551. 25:39we'll select the little icon on the
  552. 25:40right and then we'll select all of our
  553. 25:43data actually I'm going to select the
  554. 25:45column headings to right we'll go back
  555. 25:49it's grouped by columns we have labels
  556. 25:52in the first row our Alpha is 05 we're
  557. 25:55going to stick with that and we'll leave
  558. 25:57it to new worksheet ply those will give
  559. 25:59us all of our results on a new worksheet
  560. 26:02we go a and click
  561. 26:04okay and here we go so I'm going to go
  562. 26:06ahead and spread some of these columns
  563. 26:13out okay now a few things to look
  564. 26:16at actually a lot to look at so you can
  565. 26:19see that we have a summary of each score
  566. 26:22group so year one students year two
  567. 26:24students and year three students so it
  568. 26:25gives us our count the sum of all those
  569. 26:28the average and the variance in each
  570. 26:31column so we go down to the bottom
  571. 26:34that's our actual Anova table so you can
  572. 26:36see our between group sum of squares
  573. 26:3888.6 667 same thing within groups sum of
  574. 26:43squares 28 12.57 same thing total sum of
  575. 26:47squares 29.2 4 same thing degrees of
  576. 26:51freedom 2 18 and 20 good our mean
  577. 26:54squares for the with between or the
  578. 26:57columns for 4 4.33 good are within mean
  579. 27:01Square
  580. 27:02156.25 very good divide those we have an
  581. 27:07F of 2837 Etc same thing we had before
  582. 27:11now this gives us a few more bits of
  583. 27:13information which are helpful now
  584. 27:15remember that when we're doing this sort
  585. 27:17of problem we're going to test our F
  586. 27:19value of
  587. 27:212837 against an F critical value in the
  588. 27:24F distribution based on our degrees of
  589. 27:26freedom in the numerator of two
  590. 27:28and a degrees of freedom of 18 in the
  591. 27:31denominator with an alpha of 05 we
  592. 27:34learned how to do that a long time ago
  593. 27:37so our F critical is
  594. 27:4135545 so is our F statistic of
  595. 27:452837 larger or Beyond
  596. 27:493554 well no so we would fail to reject
  597. 27:53or null hypothesis that these three
  598. 27:55means are different so let's go back to
  599. 27:58our original and you can see that all
  600. 28:01this is the same now so our SPSS output
  601. 28:05we set out to replicate we did by hand
  602. 28:08over here on the left and we did it in
  603. 28:11Excel using its built-in formula now of
  604. 28:14course that's the whole point we will
  605. 28:16not do this by hand we will either use
  606. 28:17Excel or we'll use some other
  607. 28:19statistical package but I wanted to show
  608. 28:21you where all this information comes
  609. 28:23from so you can understand the
  610. 28:25foundation sort of the guts the working
  611. 28:28the gears of the Innova process so let's
  612. 28:32go ahead and go back into PowerPoint and
  613. 28:35finish everything
  614. 28:37up let's go ahead and put in our numbers
  615. 28:40from Excel so remember in Excel we found
  616. 28:43that the SSC or the sum of squares and
  617. 28:46the columns was 88.6 7 then we divide
  618. 28:51that by our degrees of freedom which is
  619. 28:53two and we end up with an MSC of 44
  620. 28:5933 now the MSE e is the
  621. 29:03SS ided 18 so that was
  622. 29:0828125 7 ided 18 and that comes out to an
  623. 29:13MSE of
  624. 29:16156.25
  625. 29:18so remember our F ratio here is the msse
  626. 29:22divided by the
  627. 29:23MSE so the mean square of the columns
  628. 29:27divided by thean mean square of the
  629. 29:29error or you can think of it as the mean
  630. 29:31Square between divided by the mean
  631. 29:34Square within so that is 44.3 3 divid
  632. 29:39156.25 and we end up with an F statistic
  633. 29:43of
  634. 29:450.28 and that is exactly what SPSS gave
  635. 29:48us and what excel's own builtin and Nova
  636. 29:52calculator gave us as well so we know we
  637. 29:54did it
  638. 29:56correctly now how do we we ultimately
  639. 29:58interpret this so our F ratio is the MSC
  640. 30:02the MSC that's what we just did now in
  641. 30:06the numerator we have a degrees of
  642. 30:07freedom of Two And in the denominator we
  643. 30:10have a degrees of freedom of 18 so
  644. 30:13remember when we look up a critical
  645. 30:15value in the F distribution we have a
  646. 30:18numerator degrees of freedom and a
  647. 30:20denominator degrees of freedom and in
  648. 30:22this case those two degrees of freedoms
  649. 30:25come from our formulas for the MSC
  650. 30:28and the m
  651. 30:30e so we can write this F statistic we
  652. 30:33got to find like this so we have an
  653. 30:36alpha level say
  654. 30:3805 then we have degrees of freedom of C
  655. 30:42of the columns and a degrees of freedom
  656. 30:44for the error E so that is the degrees
  657. 30:47of freedom in the numerator and the
  658. 30:49degrees of freedom in the denominator so
  659. 30:51we could write it like this so we need
  660. 30:53to find the critical value of f with an
  661. 30:55alpha of
  662. 30:5605 a numor gra of freedom of Two and a
  663. 31:00denominator gra of freedom of 18 and we
  664. 31:02already learned how to do that in a
  665. 31:04previous video now the easiest way is to
  666. 31:06go into Excel and use the
  667. 31:10f.v. RT function that's the F
  668. 31:13distribution the inverse right tailed
  669. 31:15that's what all that stands for and we
  670. 31:17put in those three parameters so an
  671. 31:20alpha of 05 a numerator degrees of
  672. 31:23freedom of Two and a denominator degrees
  673. 31:25of freedom of 18 so when we put that
  674. 31:28into an Excel cell we will get an F
  675. 31:31critical value of
  676. 31:363.55 so we have to ask oursel is the F
  677. 31:39statistic in our Anova table larger than
  678. 31:42our F critical value well no so remember
  679. 31:47what our no hypothesis said we talked
  680. 31:48about this in the first Anova video and
  681. 31:51these type of problems our no hypothesis
  682. 31:53is that the means are equal to each
  683. 31:56other or that's another way of saying
  684. 31:58that the means the three means come from
  685. 32:00a common
  686. 32:01population so since our F statistic is
  687. 32:04so low and does not exceed the
  688. 32:06f-critical value we fail to reject our
  689. 32:10null
  690. 32:11hypothesis so we found no significant
  691. 32:14difference in mean test score by year of
  692. 32:17student so the means of the firste
  693. 32:20students the seconde students and the
  694. 32:22third year students on their study
  695. 32:24skills exam did not differ significantly
  696. 32:27and that's
  697. 32:29it so remember up to this point we could
  698. 32:33only do comparisons involving two
  699. 32:35populations independent samples T Test
  700. 32:37and match sample T Test limiting
  701. 32:40ourselves to those two comparisons is of
  702. 32:42course limiting what if we wanted to
  703. 32:45compare the means of more than two
  704. 32:46populations like we did in this problem
  705. 32:49what if we wanted to compare the
  706. 32:50populations each containing several
  707. 32:52levels or subgroups so this get hints at
  708. 32:55the two-way Inova so imagine this
  709. 32:57scenario where we have year one students
  710. 33:01year two students and year three
  711. 33:04students but on the other axis we divide
  712. 33:07them into male and
  713. 33:09female now we have two factors so our
  714. 33:13first factor is the year of the student
  715. 33:15and our second factor is their
  716. 33:17biological sex that would be a two-way
  717. 33:20Anova and we can do that of course using
  718. 33:22this technique so the analysis of
  719. 33:25variance is the tool we use to do those
  720. 33:28more complex
  721. 33:31analyses okay so that wraps up part two
  722. 33:34of our video on the oneway Anova or the
  723. 33:36one-way analysis of variance now I know
  724. 33:39it was a lot to digest but I really
  725. 33:42wanted to take you from the very basic
  726. 33:43conceptual foundations up through an
  727. 33:46example problem so you can see how all
  728. 33:47the data is related to each other learn
  729. 33:49how to do the sum of squares and then
  730. 33:51eventually find a relationship between
  731. 33:54those sum of squares because that is the
  732. 33:55foundation of how we conduct
  733. 33:58the Inova so I have no doubt that you
  734. 34:00may need to go back and watch parts of
  735. 34:01the video to really grasp it but
  736. 34:03hopefully after watching it you have a
  737. 34:05really good solid understanding of what
  738. 34:08an NOA is so a few reminders and then
  739. 34:11we're done if you're watching the video
  740. 34:12CU you're struggling in a class stay
  741. 34:15positive and keep your head up you're an
  742. 34:17amazing smart talented person never let
  743. 34:20anyone tell you any differently
  744. 34:22including yourself if you like the video
  745. 34:25please give it a thumbs up share it with
  746. 34:27class mates or colleagues or put it on
  747. 34:29the playlist feel free to follow me here
  748. 34:31on YouTube on Twitter on Google+ or on
  749. 34:35LinkedIn it's always nice hearing from
  750. 34:38you and finally just keep in mind that
  751. 34:40the fact that you're on here trying to
  752. 34:41learn committing yourself to improving
  753. 34:44as a student or as a business person
  754. 34:47that is what really matters I firmly
  755. 34:50believe if you have the right learning
  756. 34:52process in place the results will take
  757. 34:55care of themselves so thank you very
  758. 34:57much for watching
  759. 34:58I wish you the best of luck in your
  760. 34:59studies and in your work and I look
  761. 35:01forward to seeing you again next time
  762. 35:05[Music]

About this transcript

This page contains the full transcript of YouTube transcript (UrRYITjDOww) , generated from the public captions YouTube serves with the video. The transcript has 5,618 words across 762 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.