8-2

The following is a list of 29 hospitals in the Cincinnati (Ohio) and Northern Kentucky region

a. A sample of five hospitals is to be randomly selected. The random numbers are 09, 16, 00, 49, 54, 12, and 04. Which hospitals are included in the sample?

b. A sample of five hospitals is to be randomly selected. The random numbers are 09, 16, 00, 49, 54, 12, and 04. Which hospitals are included in the sample?

8-8

A population consists of the following five values, 2,2,3,5,7

a. List all sample of size 3, and compute the mean of each sample

b. Compute the mean of the distribution of sample means and population mean

8-12

A sample of five hospitals is to be randomly selected. The random numbers are 09, 16, 00, 49, 54, 12, and 04. Which hospitals are included in the sample?

Compute the mean of the population

8-16

A normal population has a mean of 75 and a standard deviation of 5. You select a sample of 40

Compute the probability the sample mean is

a. Less than 74

b. Between 74 and 76

c. Between 76 and 77

d. Greater than 77

9-4

Suppose you know σ and you want an 85% confidence level. What value would you use as *z* in formula of confidence interval for a population mean?

9-6

A research firm conducted a survey to determine the mean amount steady smokers spend on cigarettes during a week. They found the distribution of amounts spent per week followed the normal distribution with a population standard deviation of $5. A sample of 64 steady smokers revealed that xbar = 20

What is the 95% confidence interval estimate of mu

9-10

Use Appendix B.5 to locate the value of *t* under the following conditions. **(Round your answers to 3 decimal places.)**

a. The sample size is 15 and the level of confidence is 95%

b. The sample size is 24 and the level of confidence is 98%

c. The sample size is 12 and the level of confidence is 90%

9-26

Past surveys reveal that 30% of tourists going to Las Vegas to gamble spend more than $1,000. The Visitor’s Bureau of Las Vegas wants to update this percentage.

a. The new study is to use the 90% confidence level. The estimate is to be within 1% of the population proportion. What is the necessary sample size?

b. The Bureau feels the sample size determined above is too large. What can be done to reduce the sample? Based on your suggestion, recalculate the sample size. (Hint: Use an allowable error in the range of 0.01 to 0.05)

9-28

Forty-nine items are randomly selected from a population of 500 items. The sample mean is 40 and the sample standard deviation 9.

Develop a 99% confidence interval for the population mean