1. A university surveyed recent graduates of the English department for their starting salaries. Four hundred graduates returned the survey. The average salary was $25,000, with a standard deviation of $2,500. What is the best point estimate of the population mean?

• $400

• $25,000

• $62.5

• $2,500

2. A sample standard deviation is the best point estimate of the ___________.

• population range

• population skewness

• population mode

• population standard deviation

3. A random sample of 85 supervisors revealed that they worked an average of 6.5 years before being promoted. The population standard deviation was 1.7 years. Using the 0.95 level of confidence, what is the confidence interval for the population mean?

• 6.14 and 6.86

• 6.99 and 7.99

• 4.15 and 7.15

• 6.49 and 7.49

4. Which statement(s) is(are) correct about the t-distribution?

• Its shape is symmetric.

• All of these choices are correct.

• Its dispersion is based on degrees of freedom.

• The mean is zero.

5. A total of 500 voters are randomly selected in a certain precinct and asked whether they plan to vote for the Democratic incumbent or the Republican challenger. Of the 500 surveyed, 350 said they would vote for the Democratic incumbent. Using the 0.99 level of confidence, what are the confidence limits for the proportion that plan to vote for the Democratic incumbent?

• 0.612 and 0.712

• 0.826 and 0.926

• 0.647 and 0.753

• 0.397 and 0.797

6. A survey of an urban university (population of 25,450) showed that 750 of 1,100 students sampled attended a home football game during the season. Using the 90% level of confidence, what is the confidence interval for the proportion of students attending a football game?

• [0.7510, 0.8290]

• [0.6795, 0.6805]

• [0.6659, 0.6941]

• [0.6592, 0.7044]

7. A bank wishes to estimate the mean credit card balance owed by its customers. The population standard deviation is estimated to be $300. If a 98% confidence interval is used and an margin of error of $75 is desired, how many customers should be sampled?

• 44

• 87

• 212

• 629

8. A local retail company wants to estimate the mean amount spent by customers. Their store's budget limits the number of surveys to 225. What is their maximum error of the estimated mean amount spent for a 99% level of confidence and an estimated standard deviation of $10.00?

• $1.00

• $1.72

• $10.00

• 1%

9. A sample of 50 is selected from a known population of 250 elements. The population standard deviation is 15. Using the finite population correction factor, what is the standard error of the sample means?

• 2.89

• 2.12

• Cannot be determined

• 1.90

10. A sample of 100 is selected from a known population of 350 elements. The population standard deviation is 15. Using the finite population correction factor, what is the standard error of the sample means?

• 1.9011

• 0.8464

• Cannot be determined

• 1.2695