Question 1083881: **Before you read, I have already answered #1 and for #2 I have calculated the Standard deviations, I just don't know how to answer the whole question.
Number of Books Read
Brown Black
10 12
8 14
10 18
15 9
12 12
11 8
17 14
9 18
11 16
21 14
1. Using only means, medians, and standard deviations, what are the differences in number of books read between those who wear Brown Shoes and those who wear Black Shoes based on Table #1?
***I have done this already and these are my answers: Brown Shoes: Mean= 12.4, median= 11, SD=12.18
Black shoes: mean=13.5, median=14, SD=10.12
The only question I need help with is #2
2. What is the range in number of books for those from +1 SD from the mean to -1 SD from the mean for Black Shoes? Brown Shoes?
SD for brown shoes: -12.14, -11.96, 0.22, 12.4 (mean), 24.58, 36.76, 48.84
SD for black shoes: -16.86, -6.74, 3.38, 13.5 (mean), 23.62, 33.74, 43.86
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! sd for Brown is 4.06
sd for black is 3.38
+/- 1 sd for brown is 12.4+/- 4.06=(7.94, 16.46)
+/- 1 sd for black is 13.5 +/- 3.38 =(10.12, 16.88)
Note, the sd was a lot smaller than given.
Roughly 2/3 of the data should fit between +/- 1 sd, and if it doesn't, re-calculate it.
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