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 traffic cameras, speeds averaged 67 mph. An independent samples t-test comparing the average speeds yielded a t-statistic of 10.32. 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 from this result? a. We are at least 95% confident that the average speed after the camera installation was lower than before. b. There is a 95% 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. 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 is not reported. e. We do not have enough information to draw any conclusio
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 traffic cameras, speeds averaged 67 mph. An independent samples t-test comparing the average speeds yielded a t-statistic of 10.32. 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 from this result?
a. We are at least 95% confident that the average speed after the camera installation was lower than before.
b. There is a 95% 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.
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 is not reported.
e. We do not have enough information to draw any conclusions.
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