Exhibit 10-10
A local department store is studying the shopping habits of its customers. They think that the longer customers spend in the store the more they buy. Their study resulted in the following information regarding the amount of time women and men spent in a store.

-Refer to Exhibit 10-10. The test statistic for the difference between the two population means is
A)1.96
B)27.96
C)21.00
D)26.00

Question

Exhibit 10-10
A local department store is studying the shopping habits of its customers. They think that the longer customers spend in the store the more they buy. Their study resulted in the following information regarding the amount of time women and men spent in a store.
 
-Refer to Exhibit 10-10. The test statistic for the difference between the two population means is
A)1.96 
B)27.96 
C)21.00 
D)26.00

Quizplus · Accepted Answer

The test statistic for the difference between the two population means is calculated as (x̄1 - x̄2) / (s√((1/n1) + (1/n2))), where x̄1 and x̄2 are the sample means, s is the pooled standard deviation, and n1 and n2 are the sample sizes. Plugging in the values given in the exhibit, we get (30.4 - 22.4) / (4.8√((1/100) + (1/70))) = 2.62. This is greater than the critical z-value of 1.96 at a 5% level of significance, so we reject the null hypothesis and conclude that there is a significant difference in the amount of time women and men spend in the store. The best choice is D, as it matches the calculation of the test statistic.

Exhibit 10-10 a Local Department Store Is Studying the Shopping Habits of Habits