Thousands of motorists travel on Highway 27 everyday. Before installation of traffic cameras at mile marker 11, motorists' speeds averaged 72 mph. After installation of cameras, speeds averaged 67 mph. A paired samples t-test comparing the average speeds yielded a t-statistic of 1.02. Remember, the critical value at p=.05 is 1.96. Assuming our data meet the requirements for conducting a t-test, what can we conclude? a. There is a greater than 5% chance that we would have observed this average difference if there really wasn't a difference in average speeds before and after the camera was installed. b. We cannot draw any conclusions because we should have used an independent samples t-test. c. We cannot draw any conclusions because we should have used a one-sample t-test. d. We cannot draw any conclusions because the standard deviation was not reported. e. We do not have enough information to draw any conclusions.
Thousands of motorists travel on Highway 27 everyday. Before installation of traffic cameras at mile marker 11, motorists' speeds averaged 72 mph. After installation of cameras, speeds averaged 67 mph. A paired samples t-test comparing the average speeds yielded a t-statistic of 1.02. Remember, the critical value at p=.05 is 1.96. Assuming our data meet the requirements for conducting a t-test, what can we conclude?
a. There is a greater than 5% chance that we would have observed this average difference if there really wasn't a difference in average speeds before and after the camera was installed.
b. We cannot draw any conclusions because we should have used an independent samples t-test.
c. We cannot draw any conclusions because we should have used a one-sample t-test.
d. We cannot draw any conclusions because the standard deviation was not reported.
e. We do not have enough information to draw any conclusions.
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