=+Section 13.7 19. A supermarket chain wants to know if their “buy one, get one free” campaign increases customer traffic enough to justify the cost of the program. For each of 10 stores they select two days at random to run the test. For one of those days (selected by a coin flip), the program will be in effect. They want to test the hypothesis that there is no mean difference in traffic against the alternative that the program increases the mean traffic. Here are the results in number of customer visits to the 10 stores:

Store # With Program Without Program 1 140 136 2 233 235 3 110 108 4 42 35 5 332 328 6 135 135 7 151 144 8 33 39 9 178 170 10 147 141

a) Are the data paired? Explain.