One hundred people participate in a multiplication study. They are timed to see how many single digit multiplication problems they can answer in their head without a mistake. Then, they each repeat the task with their eyes closed. For each individual, the difference in times is calculated. The purpose of the study is to determine if having your eyes opens slows down the time it takes to multiply. The hypothesis test to use is:. a. independent group means, population standard deviations known.
b. two proportions.
c. independent group means, population standard deviations unknown.
d. matched or paired samples.