Friday the 13th, traffic The British Medical Journal published an article titled, "Is Friday the 13th Bad for Your Health?" Researchers in Britain examined how Friday the 13th affects human behavior. One question was whether people tend to stay at home more on Friday the 13th. The data below are the number of cars passing Junctions 9 and 10 on the M25 motorway for consecutive Fridays (the 6th and 13th) for five different periods.

Here are summaries of two possible analyses:
Paired t-Test of ((1 - 2) = 0 vs. ((l - 2) > 0
Mean of Paired Differences: 2022.4
t-Statistic = 2.9377 with 4 df
P = 0.0212
2-Sample t-Test of (l = (2 vs. (l > (2
Difference Between Means: 2022.4
t-Statistic = 0.4273 with 7.998 df
P = 0.3402
a) Which of the tests is appropriate for these data? Explain.
b) Using the test you selected, state your conclusion.
c) Are the assumptions and conditions for inference met?

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Year Month 1990 July 1991 September 133,732 131,843 1991 December121,139118,723 1992 March 1992 November 117,584 117,263 6th 134,012 132,908 13th 124,631 120,249