Question

To compare the effectiveness of a media campaign - via radio ads, billboards, and ads on social media websites - to reduce the incidence of impaired driving, a police chief inspected data from 60 randomly chosen CheckStops at varying locations.Thirty of these were before the launch of this campaign, 30 were after the media campaign had been running for a months time. Use α=0.05α=0.05 for all calculations.

For each CheckStop randomly chosen, the number of people charged with impaired driving was recorded:
Prior: 8, 11, 10, 4, 9, 6, 4, 9, 3, 10, 2, 9, 4, 6, 5, 4, 1, 8, 5, 7, 3, 7, 4, 8, 4, 11, 4, 8, 3, 9;
After: 8, 3, 3, 3, 5, 2, 7, 6, 6, 5, 3, 9, 7, 8, 7, 5, 6, 5, 4, 3, 5, 3, 4, 3, 3, 4, 6, 4, 8, 4;

et μBeforeμBefore represent the mean number of impaired driving charges at a checkstop prior to the launch of the campaign, and μAfterμAfter be the mean number of impaired driving charges at a checkstop after the campaign has been running for a month.

(a) Does this data suggest that the variation in the number of impaired driving charges before the campaign is equal to the variation in the number of impaired driving charges after the campaign has been running for a month?
From the appropriate statistical test, find the value of the test statistic. Using at least two decimals in your answer.
Test Statistic =

(b) Report the p-value of the test you ran in (a), using at least three decimals in your answer.
P-value =

(c) Testing at α=0.05α=0.05, the null hypothesis in (a) would  ? be rejected. not be rejected.  The variation in the distribution of the number of impaired driving charges before the campaign is statistically  ? not the same the same  as the variation distribution of the number of impaired driving charges after the campaign has been running for a month.

(d) Using your findings in part (c), find a 95% confidence interval for the difference between the mean number of impaired driving charges before the media campaign and the mean number of impaired driving charges after the media campaign has been running for a month, μBefore−μAfterμBefore−μAfter.

Lower Bound of 95% CI =

(use at least three decimals)

Upper Bound of 95% CI =

(use at least three decimals)

(e) The confidence interval found in part (d) indicates that the average number of impaired driving charges before the launch of the campaign is (higher or lower or the same) the mean number of impaired driving charges after the campaign has been running for a month.

Answer 1