Chap7Stats

Chap7Stats - Review Assessment: Test Chapter 7 User...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Review Assessment: Test Chapter 7 User Elizabeth S Knowles Submitted 4/2/08 10:43 PM Name Test Chapter 7 Status Completed Score 56 out of 80 points Time Elapsed 1 hours, 20 minutes, and 16 seconds out of 3 hours and 0 minutes allowed. Instructions Question 1 2 out of 2 points Find the appropriate minimum sample size. You want to be 95% confident that the sample variance is within 40% of the population variance. Selected Answer: 56 Correct Answer: 56 Question 2 2 out of 2 points Solve the problem. Find the critical value corresponding to a sample size of 9 and a confidence level of 90 percent. Selected Answer: 2.733 Correct Answer: 2.733 Question 3 2 out of 2 points Use the given degree of confidence and sample data to construct a confidence interval for the population mean μ. Assume that the population has a normal distribution. n = 10, = 12.8, s = 4.9, 95 percent Selected Answer: 9.29 < μ < 16.31 Correct Answer: 9.29 < μ < 16.31 Question 4 2 out of 2 points Solve the problem. The following confidence interval is obtained for a population proportion, p:
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Use these confidence interval limits to find the margin of error, E. Selected Answer: 0.021 Correct Answer: 0.021 Question 5 2 out of 2 points Use the given degree of confidence and sample data to find a confidence interval for the population standard deviation σ. Assume that the population has a normal distribution. The mean replacement time for a random sample of 20 washing machines is 10.2 years and the standard deviation is 2.6 years. Construct a 99% confidence interval for the standard deviation, σ, of the replacement times of all washing machines of this type. Selected Answer: 1.8 yr < σ < 4.3 yr Correct Answer: 1.8 yr < σ < 4.3 yr Question 6 2 out of 2 points Use the given degree of confidence and sample data to construct a confidence interval for the population mean μ. Assume that the population has a normal distribution. A laboratory tested twelve chicken eggs and found that the mean amount of cholesterol was 193 milligrams with s = 15.4 milligrams. Construct a 95 percent confidence interval for the true mean cholesterol content of all such eggs. Selected Answer: 183.2 < μ < 202.8 Correct Answer: 183.2 < μ < 202.8 Question 7 2 out of 2 points Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p. When 306 college students are randomly selected and surveyed, it is found that 115 own a car. Find a 99% confidence interval for the true proportion of all college students who own a car. Selected Answer: 0.305 < p < 0.447 Correct Answer: 0.305 < p < 0.447 Question 8 0 out of 2 points Find the minimum sample size you should use to assure that your estimate of will be within the required margin of error around the population p. Margin of error: 0.01; confidence level: 95%; from a prior study,
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/27/2008 for the course MTH 157 taught by Professor Spence during the Spring '08 term at VCCS.

Page1 / 9

Chap7Stats - Review Assessment: Test Chapter 7 User...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online