MA145 Final Exam - Takehome Portion
For each of the problems below, use the MA145 technology guide to perform a statistical analysis.
You should justify your choice of method, including any assumptions made in the use of the method.
You should indicate whether a two-tailed, left-tailed, or right-tailed analysis is appropriate,
and, in hypothesis testing problems, state the null and alternative hypotheses.
If the problem does not specify a level of significance, you should choose one.
Problem 1
A retailer compares same-store sales in the months immediately before and after an ad campaign at
52 stores and finds an average increase of $12.1 (measured in thousands of dollars per week), with a standard deviation of 6.1. Does this study support the claim that the ad campaign significantly
increased sales?
Problem 2
A survey of 85 randomly selected consumers that purchased a flat-screen television in the past year
reveals that 32 selected a particular brand. Find 95 and 99 percent confidence intervals for the
market share of that brand.
Problem 3
Data from a credit card company indicates that in a certain market, families dined out an average
of 2.3 nights per week with a standard deviation of 0.8 in 2001, and 1.9 nights per week with
a standard deviation of 0.7 in 2005. Does this data indicate a significant drop in the frequency
of dining out in this market?