Question

home / study / math / statistics and probability / statistics and probability questions and answers / are women's feet getting bigger?retailers in the last 20 years have had to increase their ... Question: Are women's feet getting bigger?Retailers in the last 20 years have had to increase their stock o... Are women's feet getting bigger?Retailers in the last 20 years have had to increase their stock oflarger sizes. Wal-Mart Stores, Inc., and Payless ShoeSource, Inc.,have been aggressive in stocking larger sizes, and Nordstrom'sreports that its larger sizes typically sell out first. Assuming equal variances, at α = .025, do these random shoe size samples of 12 randomly chosen women in each agegroup show that women's shoe sizes have increased? Born in 1980: 8 7.5 8.5 8.5 8 7.5 9.5 7.5 8 8 8.5 9 Born in 1960: 8.5 7.5 8 8 7.5 7.5 7.5 8 7 8 7 8

Please explain how you got the null and alternative hypothesis. Please explain the decision rule ( so how you compared the test statistic to the level of significance). I'm having trouble figuring out what to put for these two things because sometimes the question is worded very directly and sometimes its not.

Answer 1

Born in 1980	8	7.5	8.5	8.5	8	7.5	9.5	7.5	8	8	8.5	9
Born in 1960	8.5	7.5	8	8	7.5	7.5	7.5	8	7	8	7	8

Now,

For Born in 1980:

Mean(x̅1)=8.21, Standard Deviation(s1)=0.620, n1=12

For Born in 1960:

Mean(x̅2)=7.71, Standard Deviation(s2)=0.450, n2=12

Pooled Standard Deviation(Sp):

Now,