1. Answer true or false to the following statement and give a reason for your answer: If a 95% confidence interval for a population mean, , is from 33.8 to 39.0, the mean of the population must lie somewhere between 33.8 and 39.0.

2. If you obtained one thousand 95% confidence intervals for a population mean, , roughly how many of the intervals would actually contain ?

3. Suppose we know that "a 95% confidence interval for the mean age of all U.S. millionaires is from 54.3 years to 62.8 years." Decide which of the following sentences provides a correct interpretation of the statement in quotes.

a) Ninety-five percent of all U.S. millionaires are between the ages of 54.3 years and 62.8 years.

b) There is a 95% chance that the mean age of all U.S. millionaires is between 54.3 years and 62.8 years.

c) We can be 95% confident that the mean age of all U.S. millionaires is between 54.3 years and 62.8 years.

d) The probability is 0.95 that the mean age of all U.S. millionaires is between 54.3 years and 62.8 years.

4. An analyst, using a random sample of n = 500 families, obtained a 90 percent confidence interval for mean monthly family income for a large population: ($600, $800). If the analyst had used a 99 percent confidence coefficient instead, the confidence interval would be:

a) Narrower and would involve a larger risk of being incorrect

b) Wider and would involve a smaller risk of being incorrect

c) Narrower and would involve a smaller risk of being incorrect

d) Wider and would involve a larger risk of being incorrect

e) Wider but it cannot be determined whether the risk of being incorrect would be larger or smaller

5. Why is a sample proportion generally used to estimate a population proportion instead of obtaining the population proportion directly?

6. Which of the following statements best describes the difference between a point estimate and an interval estimate?

a) A point estimate gets right to the point, while an interval estimate takes some time to be useful.

b) A point estimate specifies a best guess about a population parameter, while an interval estimate specifies a range of plausible values for the parameter

c) A point estimate provides much more information than an interval estimate.

d) While both are useful when population data is available, neither is especially useful when one only has sample data.

7. Two confidence interval estimates from the same sample are (16.4,29.8) and (14.3,31.9). What is the sample mean, and if one estimate is at the 95% level while the other is at the 99% level, which is which?

8. The real estate industry claims that it is the best and most effective system to market residential real estate. A survey of randomly selected home sellers in Illinois found that a 95% confidence interval for the proportion of homes that are sold by a real estate agent is 69% to 81%. Interpret the interval in this context.

a) 95% of all random samples of home sellers in Illinois will show that between 69% and 81% of

homes are sold by a real estate agent.

b) In 95% of the years, between 69% and 81% of homes in Illinois are sold by a real estate agent.

c) We are 95% confident that between 69% and 81% of homes in this survey are sold by a real estate agent.

d) We are 95% confident, based on this sample, that between 69% and 81% of all homes in Illinois are sold by a real estate agent.

e) 95% of all homes in Illinois are sold by a real estate agent

9. In general, the smaller the p-value, the

a) stronger the evidence against the alternative hypothesis

b) stronger the evidence for the null hypothesis

c) stronger the evidence against the null hypothesis

d) none of the above

10. Suppose the US Department of Education is interested in knowing if the proportion of high school seniors planning on attending college is different than 0.60. They conduct a hypothesis test and get a p-value of 0.039. What interpretation should they make?

a) They reject Ho, and believe that the proportion of high school seniors planning to attend college is

less than 0.60.

b) They do not reject Ho, and believe that the proportion of high school seniors planning to attend college is 0.60.

c) They reject Ho, and believe that the proportion of high school seniors planning to attend college is different than 0.60.

d) They reject Ho, and believe that the proportion of high school seniors planning to attend college is greater than 0.60.

e) They do not reject Ho, and believe that the proportion of high school seniors planning to attend college is different than 0.60.

11. The purpose of hypothesis testing is to help the researcher reach a conclusion about ?? by examining the data contained in ??.

a) a population, a sample

b) an experiment, a computer printout

c) a population, an event

d) a sample, a population