Question

(1 point) 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 200 traffic stops revealed that 38 of the drivers were under 25 years of age. A total of 132 were issued a citation while the rest were given a verbal or written warning. A total of 24 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^under25p^under25- p^over25p^over25. Round your result to four 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:H0: The difference in citation rates between younger and older drivers is due to chance.
HA:HA: Younger drivers are more likely to receive citations when stopped for speeding.


B. H0:H0: Younger drivers are more likely to receive citations when stopped for speeding.
HA:HA: The difference in citation rates between younger and older drivers is due to chance.


C. H0:H0: The difference in citation rates between younger and older drivers is due to chance.
HA:HA: Younger drivers are less likely to receive citations when stopped for speeding.


D. H0:H0: Younger drivers are less likely to receive citations when stopped for speeding
HA:HA: The difference in citation rates between younger and older drivers is due to chance.

5. Report your p-value here:

6. Based on the p-value, we have:
A. extremely strong evidence
B. very strong evidence
C. little evidence
D. some evidence
E. strong evidence
that the null model is not a good fit for our observed data.

Answer 1

1.

Age	Citation	Warning	Total
Under 25	24	38-24=14	38
25 or older	162-54=108	68-14=54	200-38=162
Total	132	200-132=68	200

2. Option: B. Observational Study

4. Option: C. 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.

6. Option: C. little evidence