Question

The manager of a single department store wants to determine if newspaper advertising really does affect sales. For the experiment, the manager randomly selects 15 items in stock and records how much of each item was sold in a one-week period. Then, without changing the price on these same 15 items, the manager places a large ad in the newspaper advertising these items. Again the manager records how much of each of these 15 items were sold in a one-week period. What is the appropriate analysis?

Answer 1

The store manager should use a paired sample t-test to analyze the impact of newspaper advertising on sales of 15 items by comparing sales before and after advertising; it helps determine if there's a statistically significant difference.

Step-by-step explanation:

To determine if newspaper advertising affects sales, the store manager has conducted a before-and-after study, measuring the sale of 15 items with and without advertising. The appropriate analysis for this experiment would be a paired sample t-test (also known as the dependent sample t-test), which compares the means of two related groups to determine whether there is a statistically significant difference between these means.

In the case of the department store, the sale amounts of the 15 items before the advertisement serve as the first group, and the sale amounts after the advertisement serve as the second group. This type of analysis will show whether the variations in sales are significant enough to suggest that the newspaper advertising had an effect. If the p-value is less than the chosen alpha level (commonly 0.05), we would reject the null hypothesis and conclude that the advertising did have a significant effect on sales.