Weekend HW =Please complete the following:
Page 124: 17, 18
- For each problem:
- First, draw the Normal model and label the correct data values for 1,2, and 3 standard deviations above the mean (using the mean, standard deviation given); this is part (a) of each question
- Then, use this picture/model and the percentages (see the image below) in each region to answer the subsequent questions!
- *For #'s 17 and 18 you must read pages 109-111 in your textbook to figure this out! Also use the image below.You got this!
- Read from "The 68-95-99.7 rule" (p. 109) and stop when you get to "Finding Normal Percentiles by hand" (p. 111)
- You can also try to look up some videos on "The Empirical Rule" using Khan Academy or the links to the right to help with this!
Today's Class Recap:
- Stamp = shifting + rescaling practice
- Discussed HW questions
- Back to ch. 6 notes: developed the z-score formula as a class
- If you were out read about z-scores in chapter 6 of your book!
- Talked about z-scores: what is the mean and standard deviation for z-scores?
Monday's HW: (if you'd like to get a head start)--this is based on what we learned today
(z-scores) and what you'll teach yourself this weekend, so you can (probably) get this all done this weekend if you like!
Page 123: 5, 7, 13, 23, 27
Matching Classwork Key:
- Remember when we completed some classwork in groups, matching histograms to boxplots and matching variables to boxplots?
- I only graded one per group, so you may not know if your answers are correct....
- Here are the correct answers--it would be a good idea to grade your own!
- Matching Histograms to Variables:
- Histogram A = Variable 2
- Distribution is roughly symmetric, so the mean and median are (roughly) the same, but the data isn't very concentrated in the center so the standard deviation is large (larger than variable 6, which is also roughly symmetric)
- Histogram B = Variable 1
- This histogram is skewed right, so the mean is greater than the median;
- Histogram C = Variable 5
- I would've done this one first, this is skewed left, so the mean has to be less than the median, which only leaves variable 5 as an option
- Histogram D = Variable 4
- I would've done this one second; this definitely has the largest standard deviation because so much data is "on the outsides," so this has to be variable 4
- Histogram E = Variable 3
- We should be debating between histograms B/E for variables 1/3--look at the x-axis! The values on the x-axis of histogram B are much larger, so histogram B would have to have the larger mean (and for both the mean is larger than the median).
- Histogram F = Variable 6
- This is roughly symmetric; most of the data is clustered in the center, so this would have a small standard deviation (smaller than variable 1); we'd debate between variables 2 and 6, but this histogram has the smaller standard deviation of the two
- Matching Histograms and Boxplots
- Histogram A = Boxplot 2
- Histogram B = Boxplot 3
- Histogram C = Boxplot 4
- Histogram D = Boxplot 1
- Histograms C and D should've been easy to match based on skewness...
- That leaves us with a debate between Histograms A/B and Boxplots 2/3; I'd look at the IQR here. Boxplot 2 has a wider IQR than boxplot 3. Histogram b is more concentrated in the middle, so it would have the smaller IQR (boxplot 3), where histogram A is more spread out in the middle 50% (less concentrated in the middle), so it would have the larger IQR (boxplot 2).
Lastly, here is the create/compare boxplots homework key so you can look at it in more detail:
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