Question

A random sample of 6 fields of corn has a mean yield of 21.6 bushels per acre and standard deviation of 6.02 bushels per acre. Determine the 99%confidence interval for the true mean yield. Assume the population is approximately normal.

A. Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.

B. Construct the 99% confidence interval. Round your answer to one decimal place.

Lower endpoint: ______ Upper endpoint: ______

A quality-conscious disk manufacturer wishes to know the fraction of disks his company makes which are defective.Suppose a sample of 609 floppy disks is drawn. Of these disks, 536 were not defective.

A. Using the data, estimate the proportion of disks which are defective. Enter your answer as a fraction or a decimal number rounded to three decimal places.

B. Using the data, construct the 90% confidence interval for the population proportion of disks which are defective. Round your answers to three decimal places.

   Lower endpoint: ______ Upper endpoint: ______

The American Heart Association is about to conduct an anti-smoking campaign and wants to know the fraction of Americans over 44 who smoke. Suppose a sample of 2653 Americans over 44 is drawn. Of these people, 2149 don't smoke.

A. Using the data, estimate the proportion of Americans over 44 who smoke. Enter your answer as a fraction or a decimal number rounded to three decimal places.

B. Using the data, construct the 99% confidence interval for the population proportion of Americans over 4444 who smoke. Round your answers to three decimal places.

Lower endpoint: ______ Upper endpoint: ______

Answer 1