business statistics
posted by Samantta .
The International Council of Shopping Centers reports that the average teenager spends $39 during a shopping trip to the mall. The promotions director of a local mall has used a variety of strategies to attract area teens to his mall, including live bands and “teenage group. He believes teen shoppers at his mall respond to his promotional efforts by shopping there more often and spending more when they do. Mall management decides to evaluate the promotions director’s success by surveying a simple random sample of 45 local teens and finding out how much they spent on their most recent shopping visit to the mall. The results are listed in data file XR10056. Use a suitable hypothesis test in examining whether the mean mall shopping expenditure for teens in this area might be higher than for U.S. teens as a whole. Indentify and interpret the pvalue for the test. Using the 0.025 level of significance, what conclusion do you reach?

For a Z score, find the difference between means divided by the standard error of the means.
H0: mean 1 = mean 2
H1: mean 1 < mean 2
If p > .025, accept null hypothesis (H0). If p < .025, accept H1.
You should have adequate data to do this.
I hope this helps. Thanks for asking. 
You should divide by the standard error for the difference between means. Sorry.