Independence samples ttest for unequal variance.
Harriet's Shoe Emporium operates stores in enclosed shopping malls in addition to outlet malls. There are more than 1,000 stores throughout the United States and Canada. Harriet, the CEO, wishes to determine whether the number of shoes sold per week at mall stores is more than the number sold at outlet malls. She selects a sample of 22 mall and 25 outlet stores and determines the number of shoes sold in each sample store last week. The sample information is reported below.
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Sample Mean

Sample Standard Deviation

Sample Size

Mall

1,078

633

22

Outlet

908.2

369.8

25

Harriet believes there is much more variation in the number of shoes sold in mall stores than in the outlet stores. Hence, she is not willing to assume equal population standard deviations. At the .02 significance level is it reasonable to conclude that the mean number of shoes sold at mall stores is larger than at outlet stores?