# Question: A researcher wants to determine a 99 confidence interval for

A researcher wants to determine a 99% confidence interval for the mean number of hours that adults spend per week doing community service. How large a sample should the researcher select so that the estimate is within 1.2 hours of the population mean? Assume that the standard deviation for time spent per week doing community service by all adults is 3 hours.

## Relevant Questions

An economist wants to find a 90% confidence interval for the mean sale price of houses in a state. How large a sample should she select so that the estimate is within $3500 of the population mean? Assume that the standard ...For a data set obtained from a sample, n = 81 and . It is known that σ = 4.8. a. What is the point estimate of µ? b. Make a 95% confidence interval for µ. c. What is the margin of error of estimate for part b? At the end of Section 8.2, we noted that we always round up when calculating the minimum sample size for a confidence interval for µ with a specified margin of error and confidence level. Using the formula for the margin of ...For a population data set, σ = 12.5 a. How large a sample should be selected so that the margin of error of estimate for a 99% confidence interval for µ is 2.50? b. How large a sample should be selected so that the margin ...At Farmer’s Dairy, a machine is set to fill 32-ounce milk cartons. However, this machine does not put exactly 32 ounces of milk into each carton; the amount varies slightly from carton to carton. It is known that when the ...Post your question