Some types of periodicals are often browsed on the shelves but seldom purchased. A popular home improvement magazine now puts a seal on its monthly issues to prevent people from leafing through, lifting ideas, and then walking away without buying. As the publisher of another popular home improvement magazine, you introduced this idea to your editorial board. However, while some members of your board believed this practice would increase sales, others believed that inability to leaf through the magazine might actually decrease sales. To settle the disagreement, you decided to place seals on your magazines 12 months ago, at which time average monthly sales had historically been 750,000 per issue. Sampling the 12-month period since your decision, monthly sales have averaged 708,000 with a standard deviation of 50,500. Assume the distribution of monthly magazine sales is normal. Perform the appropriate hypothesis test necessary to evaluate both of the concerns brought up by your editorial board. Use the p-value approach and a significance level of 5%
a. What are your hypotheses?
b. What is the p-value of your test?
c. What conclusion should you draw regarding the effect that sealing the magazines has on monthly sales?