A study of 203 police officers in an eastern state found that their sample mean salary was $75,500 with a sample standard deviation of $3,000. The same study of 245 police officers in a northern state found that their sample mean salary was $74,500 with a sample standard deviation of $4,000.

[Use the below information for the empirical rule: Question 4 through Question 9]

Suppose that the population mean of all the police officers in an eastern state is $75,000 with a standard deviation of $2,000, and the population mean of all the police officers in a northern state is $74,000 with a standard deviation of $2,000.

Let group 1 be the eastern state police officers, and group 2 be the northern state police officers.

1. What is the point estimate of?

2. What is the point estimate of?

3. What is the point estimate of the difference between two means,?

If the shapes of both groups' data are bell shapes, use the empirical rule to answer the below problems.

4. Find the lower bound of the best interval, which includes about 95% of all the police officers' salaries in an eastern state.

5. Find the upper bound of the best interval, which includes about 95% of all the police officers' salaries in an eastern state.

6. Find the lower bound of the best interval, which includes about 68% of all the police officers' salaries in a northern state.

7. Find the upper bound of the best interval, which includes about 68% of all the police officers' salaries in a northern state.

8. Using the same principle, find the lower bound of the 95% interval for the mean difference between all the police officers in the two states. (Note that the mean difference is $1,000 and the standard deviation of the mean difference is approximately $2,800.)

9. Using the same principle, find the upper bound of the 95% interval for the mean difference between all the police officers in the two states. (Note that the mean difference is $1,000 and the standard deviation of the mean difference is approximately $2,800.)