Question

a researcher wants to determine whether shoppers will spend more money at the grocery when they use a credit card to pay for their groceries rather than cash. in which situation could the researcher use a hypothesis test for matched pairs?
a. the researcher randomly assigns half of the sample to only use cash for their grocery shopping for one trip to the grocery store. the other half of the sample uses only credit cards. the researcher compares the amount of money spent by each of the two groups.
b. the researcher asks the people in the sample whether they prefer to shop for their groceries using a credit card more than with cash (yes/no).
c. the people in the experiment are told to use only cash for their grocery shopping for one trip and report how much money they spent. the next trip, the same people in the sample use only credit cards for their grocery shopping and calculate the total. the researcher compares the total spent by each individual to see if they spent more, on average, when using cash or the credit card.

Explanation:

Matched - pairs hypothesis test is used when the same subjects are measured under two different conditions. In option C, the same people are measured (their grocery - spending amount) under two conditions: using cash and using a credit card. In option A, two different groups are used (not the same subjects), and in option B, it is a preference (yes/no) question which is not a quantitative comparison of the same subjects under two conditions.

Answer:

C. The people in the experiment are told to use only cash for their grocery shopping for one trip and report how much money they spent. The next trip, the same people in the sample use only credit cards for their grocery shopping and calculate the total. The researcher compares the total spent by each individual to see if they spent more, on average, when using cash or the credit card.