Question

Law enforcement agencies in Charlotte, NC conduct an average of 120,000 traffic stops per year. By law, the agencies collect information about all traffic stops, the reason for the stop, and the type of enforcement action taken. A random sample of 300 traffic stops revealed that 63 of the drivers were under 25 years of age. A total of 198 were issued a citation while the rest were given a verbal or written warning. A total of 42 drivers were under 25 years of age and issued a citation.

1. Use this information to complete the contingency table below.
Age Citation Warning Total
Under 25
25 or older
Total
2. What type of a study is this?
A. Experiment
B. Observational Study
3. Compute the difference in the proportions of drivers who received a citation in the two groups:_____.
p^under25
- p^over25.
Round your result to three decimal places.
4. Insurance rates are usually higher for drivers under the age of 25. Which set of hypotheses would we use to test whether this was justified?
A. H0:
The difference in citation rates between younger and older drivers is due to chance.
HA: Younger drivers are less likely to receive citations when stopped for speeding.
B. H0: Younger drivers are less likely to receive citations when stopped for speeding
HA: The difference in citation rates between younger and older drivers is due to chance.
C. H0: Younger drivers are more likely to receive citations when stopped for speeding.
HA: The difference in citation rates between younger and older drivers is due to chance.
D. H0: The difference in citation rates between younger and older drivers is due to chance.
HA:
Younger drivers are more likely to receive citations when stopped for speeding.
5. Use the Two Proportion Resampling Test app (both linked and embedded below) to conduct this test. Report your p-value here:

Answer 1

1. Citation Total 198

Warning Total 102

Total 300

2. Observational

3. 25%

4. B. H0 : Younger drivers are less likely to receive citation when stopped for speeding

HA : The difference in citation rates between younger and older drivers is due to chance.

5. 1.0258

Explanation:

Citation

Under 25 years : 42

Above 25 years: 156

Total : 198

Warning :

Under 25 years : 21

Above 25 years: 81

Total : 102