Chapter 7 review Lilly

What'a your favorite stat law/theorem?

• law of large numbers

• Empirical rule

• Central limit theorem

• Chebyshev's theorem

What is the point estimate for a population proportion? 

• population mean

• sample proportion
• population proportion
• sample median

Windy place: Mt. Washington, New Hampshire, is one of the windiest places in the United States. Wind speed measurements on a simple random sample of 50 days had a sample mean of 47.37mph. We know that the sample standard deviation is 22.3mph.

To construct a confidence interval for the mean, what method is appropriate here?

• • Z method, because we have the population standard deviation.

• • T method, because we have the sample standard deviation.

• • Neither method is appropriate, since the sample size is too small and we do not know if the population is approximately normal.

SAT scores: A college admissions officer takes a simple random sample of 100 entering freshmen and computes their mean mathematics SAT score to be 440. Assume the population standard deviation is 113. A 99.9% confidence interval is wanted for the mean mathematics SAT score for the entering freshman class.

What method are you supposed to use for this interval?

• Z method for population mean

• Z method for population proportion

• T method for population proportion

• T method for population mean

SAT scores: A college admissions officer takes a simple random sample of 100 entering freshmen and computes their mean mathematics SAT score to be 440. Assume the population standard deviation is 113. A 99.9% confidence interval is wanted for the mean mathematics SAT score for the entering freshman class.

What are the assumptions for this confidence interval?

• The sample is a SRS

• The sample size is large enough np>10 and n(1-p)>10

• The sample size is large enough n>30

• The confidence level is large enough

SAT scores: A college admissions officer takes a simple random sample of 100 entering freshmen and computes their mean mathematics SAT score to be 440. Assume the population standard deviation is 113. A 99.9% confidence interval is wanted for the mean mathematics SAT score for the entering freshman class.

Find the point estimate.

• The point estimate is the sample mean x bar= 440

• The point estimate is the population mean = 440

• The point estimate is the sample proportion p hat= 0.227

• The point estimate is the population proportion p= 0.227

SAT scores: A college admissions officer takes a simple random sample of 100 entering freshmen and computes their mean mathematics SAT score to be 440. Assume the population standard deviation is 113. A 99.9% confidence interval is wanted for the mean mathematics SAT score for the entering freshman class.

Find the critical value.

• 3.29

• 2.78

• 1.96

• 3.45

SAT scores: A college admissions officer takes a simple random sample of 100 entering freshmen and computes their mean mathematics SAT score to be 440. Assume the population standard deviation is 113. A 99.9% confidence interval is wanted for the mean mathematics SAT score for the entering freshman class.

Find the standard error.

• 10.25

• 8.65

• 11.30

• 7.3

SAT scores: A college admissions officer takes a simple random sample of 100 entering freshmen and computes their mean mathematics SAT score to be 440. Assume the population standard deviation is 113. A 99.9% confidence interval is wanted for the mean mathematics SAT score for the entering freshman class.

Find the margin of error.

• 3

• 45

• 37

• 23

SAT scores: A college admissions officer takes a simple random sample of 100 entering freshmen and computes their mean mathematics SAT score to be 440. Assume the population standard deviation is 113. A 99.9% confidence interval is wanted for the mean mathematics SAT score for the entering freshman class.

Construct the confidence interval.

• We are 99.9% confident that the population mean math SAT score is between 415 and 477

• We are 99.9% confident that the population mean math SAT score is between 403 and 477

• We are 0.01% confident that the population mean math SAT score is between 403 and 477

• We are 99.9% confident that the population mean math SAT score is between 469 and 477