Question: A researcher uses a matched-samples design to investigate whether single people who own pets are generally happier than singles without pets. A mood inventory questionnaire is administered to a group of 20- to 29-year-old non–pet owners and a similar age group of pet owners. The pet owners are matched one to one with the non–pet owners for income, number of close friendships, and general health. The data are as follows:

Matched Pair Non-Pet Owner Pet Owner

A 10 15

B 9 9

C 11 10

D 11 19

E 5 17

F 9 15

Is there a significant difference in the mood scores for non–pet owners versus pet owners? Test with α = .05 for two tails.