1. The Willow Run Outlet Mall has two Haggar Outlet Stores, one located on Peach Street and the other on Plum Street. The two stores are laid out differently, but both store managers claim their layout maximizes the amounts customers will purchase on impulse. A sample of 10 customers at the Peach Street store revealed they spent the following amounts more than planned: $17.58, $19.73, $12.61, $17.79, $16.22, $15.82, $15.40, $15.86, $11.82, $15.85. A sample of 14 customers at the Plum Street store revealed they spent the following amounts more than they planned when they entered the store: $18.19, $20.22, $17.38, $17.96, $23.92, $15.87, $16.47, $15.96, $16.79, $16.74, $21.40, $20.57, $19.79, $14.83. For data analysis, a t test: two-sample assuming unequal variances was used.
Hypothesis Test: Independent Groups (t test, unequal variance)
Peach Street Plum Street
15.8680 18.2921 Mean
2.3306 2.5527 std. dev.
10 14 n
20 df
-2.42414 difference (Peach Street - Plum Street)
1.00431 standard error of difference
0 hypothesized difference
-2.41 t
.0255 p-value (two-tailed)
-5.28173 confidence interval 99.% lower
0.43345 confidence interval 99.% upper
2.85759 margin of error
At the .01 significance level, is there a difference in the mean amount purchased on an impulse at the two stores? Explain these results to a person who knows about the t test for a single sample but who is unfamiliar with the t test for independent means.