XYZ Mat 120 Module 1 Lesson 1 4 — Transcript

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1. 0:00this is module 1 lesson 1.4
2. 0:03on graphs we're going to look at a few
3. 0:06different types of graphs in this
4. 0:07section
5. 0:08the first one is a stem plot sometimes
6. 0:11it's called a stem and leaf plot
7. 0:13they're representing quantitative data
8. 0:15by separating
9. 0:17each value into two parts and so
10. 0:20it's looking at digits the leftmost
11. 0:23digit
12. 0:24and then the rightmost digit and so you
13. 0:26can think of that
14. 0:27as being tens and ones
15. 0:30or it could be hundreds and tens
16. 0:34and ones but for this particular problem
17. 0:37we're looking at pulse rates
18. 0:38and so think of this as being your tens
19. 0:42column
20. 0:43and this one is me and your ones column
21. 0:46and when we're writing these
22. 0:48we can see that the pulse rates for the
23. 0:50four
24. 0:51would be 40 and 42
25. 0:54so the zero is a value that gives us the
26. 0:5840
27. 0:59and then the 4 goes with the 2 also so
28. 1:0142.
29. 1:03look at the 5. you've got 50 you've got
30. 1:0650.
31. 1:07and then you have lots of 52s so you
32. 1:10would have to write each of those
33. 1:12and then lots of 54s 256s
34. 1:17and lots of 58s and then we'll go to six
35. 1:21lots of 60s 62s 64 66 68
36. 1:26and then 70s 80s 90s and then 100 so
37. 1:29this would be
38. 1:30102 and then
39. 1:33104. so
40. 1:36looking at these you can look at this
41. 1:38graph and you can tell immediately
42. 1:41that the majority of pulse rates are
43. 1:44falling
44. 1:44in the 60s because just a quick glance
45. 1:47will tell me that the majority sits here
46. 1:50and then the second one would be in the
47. 1:5270s
48. 1:53so that's a stem-and-leaf plot and
49. 1:55that's how you interpret that
50. 1:58now here's a data set that you're asked
51. 2:00to recreate or
52. 2:02create a stem-and-leaf plot and this is
53. 2:04from your homework
54. 2:06and it says use the data to complete the
55. 2:09last row
56. 2:10of the stem and leaf plot so we just
57. 2:12want the last row of the stem and leaf
58. 2:14plot
59. 2:14they've already done the 60s they've
60. 2:16already done the 70s
61. 2:18they did the 80s and now we're asked to
62. 2:20find the 90s
63. 2:21so i went up here and i looked in my
64. 2:24chart
65. 2:24for all of the 90s i found a 98
66. 2:28i found a 94 and i found a 91.
67. 2:31so i want to put 91 first we'll start
68. 2:34with smallest
69. 2:3694 seconds and we'll put the 4 second
70. 2:39and then 98 last and so that tells me i
71. 2:42have a 91
72. 2:43a 94 and a 98 in addition to all of
73. 2:46these others we can see
74. 2:48the majority falls in the 70s it's also
75. 2:50important that we go
76. 2:516 7 8 9 we don't skip any of those even
77. 2:55though
78. 2:55there might not be anything for one of
79. 2:57the categories we still want to keep
80. 2:59these in order
81. 3:01now another example using
82. 3:04the stem and leaf um it says how many
83. 3:08data values are in the set
84. 3:09so if i look here i know that the first
85. 3:12one is a 45
86. 3:14then we have a 47 then we have a 49.
87. 3:16that's three data values
88. 3:18and then i could list the others 55 56
89. 3:2156
90. 3:2158 58 and then 62
91. 3:2464 66 and 68 then i'll have a 71 and
92. 3:29then i'll have a 77 i'm not going to sit
93. 3:30here and list
94. 3:31all of those but i counted each of them
95. 3:33so that's 3
96. 3:357 8 19 11 12 13 14 they're a total of
97. 3:3814 data values what's the minimum value
98. 3:42for the last
99. 3:43class so i want the minimum for the last
100. 3:46class here's my last class
101. 3:48the minimum value is 71. how many
102. 3:51original values are greater than or
103. 3:53equal to 60. so if i look at this
104. 3:56here's my 60s so greater than or equal
105. 3:59to
106. 4:00so for this one i'll have 62 64
107. 4:0466 and 68 and then 71
108. 4:07and 77 so that is six values
109. 4:12that are greater than or equal to 60.
110. 4:14and then it says what percent of values
111. 4:16are greater than or equal to 60. so we
112. 4:18said there's six of them
113. 4:19it's a total of 14. so we'll take 6
114. 4:22divide it by 14
115. 4:23and we'll get 0.428 so just in my
116. 4:27calculator
117. 4:286 divided by 14 is 0.42857
118. 4:32we want to write this to the nearest
119. 4:34whole percentage
120. 4:36so the nearest whole number in terms of
121. 4:38percentage that would be
122. 4:4042
123. 4:44percent so that's 42 so 42.8
124. 4:49um if it said the i'm sorry the nearest
125. 4:51whole number
126. 4:52so let's change that the nearest whole
127. 4:54number that's going to be 43. so let me
128. 4:56just erase that 42.8 percent rounded to
129. 4:59the nearest whole number
130. 5:00is 43 then
131. 5:04we're going to look at a pareto chart a
132. 5:06pareto chart
133. 5:07is a bar graph but notice
134. 5:11it's got to be in decreasing order
135. 5:14so in decreasing order we have
136. 5:17our bar graph so this happens to be
137. 5:20stolen boats
138. 5:22and we have jet skis motorboats fishing
139. 5:24boats and board boats and sailboats and
140. 5:26so
141. 5:26the big deal about pareto is that we
142. 5:29have a bar graph
143. 5:30and it's got to be in decreasing order
144. 5:33so in your homework
145. 5:35you're asked to identify a pareto chart
146. 5:37so looking at these which one is a
147. 5:39pareto chart
148. 5:40well this one is not because it
149. 5:42increases
150. 5:44this one is just a histogram because
151. 5:46it's all over the place
152. 5:48another histogram but this one is a
153. 5:50pareto chart because it's in decreasing
154. 5:53order
155. 5:53so this would be my answer because it's
156. 5:56in decreasing order
157. 5:57just the same as a histogram but we have
158. 5:59to just change the order
159. 6:01the other type of graph is a dot plot
160. 6:04dot plot uses quantitative data and
161. 6:06you're just going to put a point or a
162. 6:08dot
163. 6:09on the horizontal scale and so this is
164. 6:11just like a number line
165. 6:12we've got pulse rates of males and so
166. 6:14we're just putting dots where we have
167. 6:16each of these values
168. 6:17so i could read some of these values the
169. 6:19first one you see is 40.
170. 6:22that would be one of my data values and
171. 6:23then this next dot was probably a 41
172. 6:26then i come over here and i have 50 i
173. 6:29have two dots so that means i have two
174. 6:3150s in my data set
175. 6:33and then one two three four five i have
176. 6:36like five
177. 6:37fifty ones and so we have to just list
178. 6:41them all if we're listing them in our
179. 6:42data set
180. 6:43and then you can go over here and you've
181. 6:44got a whole bunch of them right here and
182. 6:48then your 70s
183. 6:49and then all the way over here you got a
184. 6:5290
185. 6:5291 92 whatever that happens to be so you
186. 6:55could list
187. 6:56each of those and it's a bunch of them
188. 6:57because you'd have to account for every
189. 6:59single dot
190. 7:00so now this one says draw a dot plot
191. 7:04for this set of data so we're going to
192. 7:08start off
193. 7:09and we have 35 so we'll start off with
194. 7:1235 so i got one
195. 7:14on 35 i've got 27
196. 7:19and then another 27 and then a 30
197. 7:24and then a 32 you can kind of see what
198. 7:26we're doing it's just really easy
199. 7:29to do these and then we'll do a 29
200. 7:33and then we've got it um 27
201. 7:3634 27 so another 27 another 27 and then
202. 7:39a 34
203. 7:41just kind of taking these straight
204. 7:43across and i've got a 33
205. 7:45i have a 26 a 35
206. 7:49another 35 so you can see how my dots
207. 7:51are going here
208. 7:53another 33 a 25
209. 7:56and we have a 29 again and a 34 again
210. 8:00and we have two 26s a 28
211. 8:04so we'll start down here always at the
212. 8:06bottom and then we'll have 34 and 31.
213. 8:08so that's your dot plot so that's how
214. 8:10you would do these in your homework
215. 8:13and then the last one i have is
216. 8:16interpreting the dot plot so these dot
217. 8:18plots are given and it says how many
218. 8:19data items do we have
219. 8:21well you've got to count every single
220. 8:23dot so every single dot represents the
221. 8:25data value so we have 23 dots so that
222. 8:28means i have a total of 23
223. 8:30data items what is the mode the mode is
224. 8:33the one that occurs the most
225. 8:35so if i look at this which one occurs
226. 8:37the most well i can see
227. 8:40that we have three that occur the most
228. 8:42they all
229. 8:43occur four times i have 25 occurs
230. 8:46four times 28 occurs
231. 8:49four times and 31 occurs four times so
232. 8:53all of those would
233. 8:55be um consisting of the mode because
234. 8:58none of them occur more than any of the
235. 9:00others what presented values are greater
236. 9:03than 29 so i'm going to figure out how
237. 9:05many are greater than 29 so here's my 29
238. 9:07don't count those
239. 9:09so we'll count all of these 7 8 9 10. so
240. 9:12i have 10 that are greater than 29
241. 9:15i have a total of 23 and we want a
242. 9:18percent
243. 9:19answer with a whole number so just like
244. 9:21we did before we're going to do 10
245. 9:23divided by 23 and we'll have 0.4347 so
246. 9:330.4347
247. 9:35we want to round that to the nearest
248. 9:36whole number so that would be 43 percent
249. 9:42and that's some of your questions that
250. 9:44you will have from your homework