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Chapter 8: Q.2 (page 481)

Got shoes? The class in Exercise 1 wants to estimate the variability in the number of pairs of shoes that female students have by estimating the population variance 蟽2.

Short Answer

Expert verified

The sample variance is s2=202.7658.

Step by step solution

01

Given Information

Data:

02

Explanation

The mean (or average) is the sum of all values divided by the number of values:

x炉=50+26+鈥�+15+5120=30.35

nis the number of values in the data set.

n=20

The sample variance is the sum of squared deviations from the mean divided by n-1:

s2=鈭�(x-x炉)2n-1

(50-30.35)2+(26-30.35)2+(26-30.35)2+(31-30.35)2+(57-30.35)2

+(19-30.35)2+(24-30.35)2+(22-30.35)2+(23-30.35)2+(38-30.35)2

+(13-630.35)2+(50-30.35)2+(13-30.35)2+(34-30.35)2+(23-30.35)2

+(30-30.35)2+(49-30.35)2+(13-30.35)2+(15-30.35)2+(51-30.35)220-1

=202.7658

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