Question 10.32

fridaythe13th

32. Does Friday the 13th Change Human Behavior? In Example 4 of Chapter 1, we discussed whether Friday the 13th changed human behavior. The researchers obtained data kept by the British Department of Transport on the traffic flow through certain junctions of the M25 motorway in England.4

  1. Find the mean of the differences, , and the standard deviation of the differences, .
  2. Perform the appropriate hypothesis test for determining whether the mean traffic flow is smaller for Friday the 13th compared with Friday the 6th, using level of significance . Assume normality.
Table 10.15: Table 6 Traffic through M25 junctions
Friday the 6th Friday the 13th Difference
139,246 138,548 698
134,012 132,908 1104
137,055 136,018 1037
133,732 131,843 1889
123,552 121,641 1911
121,139 118,723 2416
128,293 125,532 2761
124,631 120,249 4382
124,609 122,770 1839
117,584 117,263 321