Question #1

You are the operations manager for an airline and you are considering a higher fare level for passengers in aisle seats. How many randomly selected air passengers must you survey? Assume that you want to be 90% confident that the sample percentage is within 3.5 percentage points of the true population percentage. Complete parts (a) and (b) below.

a. Assume that nothing is known about the percentage of passengers who prefer aisle seats.

_______= nothing

(Round up to the nearest integer.)

b. Assume that a prior survey suggests that about 33% of air passengers prefer an aisle seat.

_______= nothing

(Round up to the nearest integer.)

Question #2

A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before treatment, 16 subjects had a mean wake time of 104.0 min. After treatment, the 16 subjects had a mean wake time of 82.7 min and a standard deviation of 22.2 min. Assume that the 16 sample values appear to be from a normally distributed population and construct a 90% confidence interval estimate of the mean wake time for a population with drug treatments. What does the result suggest about the mean wake time of 104.0 min before the treatment? Does the drug appear to be effective?

Construct the 90% confidence interval estimate of the mean wake time for a population with the treatment.

__________ min < < __________ min

(Round to one decimal place as needed.)

What does the result suggest about the mean wake time of 104.0 min before the treatment? Does the drug appear to be effective?

The confidence interval ____________ ( A. includes, B. does not include ) the mean wake time of 104.0 min before the treatment, so the means before and after the treatment

__________ ( A. could be the same, B. are different ) This result suggests that the drug treatment ______________ ( A. has, B. does not have ) a significant effect.

Question #3

An IQ test is designed so that the mean is 100 and the standard deviation is 18 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 99% confidence that the sample mean is within 4 IQ points of the true mean. Assume that =18 and determine the required sample size using technology. Then determine if this is a reasonable sample size for a real world calculation.

The required sample size is __________. (Round up to the nearest integer.)

Would it be reasonable to sample this number of students?

A. No. This number of IQ test scores is a fairly small number.

B. Yes. This number of IQ test scores is a fairly large number.

C. No. This number of IQ test scores is a fairly large number.

D. Yes. This number of IQ test scores is a fairly small number.

Question #4

Use the sample data and confidence level given below to complete parts (a) through (d).

A drug is used to help prevent blood clots in certain patients. In clinical trials, among 4666

patients treated with the drug, 185 developed the adverse reaction of nausea. Construct a

99% confidence interval for the proportion of adverse reactions.

a) Find the best point estimate of the population proportion p.

____________

(Round to three decimal places as needed.)

b) Identify the value of the margin of error E.

E = ___________

(Round to three decimal places as needed.)

c) Construct the confidence interval.

_________ < p < __________

(Round to three decimal places as needed.)

d) Write a statement that correctly interprets the confidence interval. Choose the correct answer below.

A. There is a 99% chance that the true value of the population proportion will fall between the lower bound and the upper bound.

B.99% of sample proportions will fall between the lower bound and the upper bound.

C. One has 99% confidence that the sample proportion is equal to the population proportion.

D. One has 99% confidence that the interval from the lower bound to the upper bound actually does contain the true value of the population proportion.