# Question: When one is attempting to determine the required sample size

When one is attempting to determine the required sample size for estimating a population mean, and the information on the population standard deviation is not available, it may be feasible to take a small preliminary sample and use the sample standard deviation to estimate the required sample size, n. Suppose that we want to estimate µ, the mean commuting distance for students at a community college, to a margin of error within 1 mile with a confidence level of 95%. A random sample of 20 students yields a standard deviation of 4.1 miles. Use this value of the sample standard deviation, s, to estimate the required sample size, n. Assume that the corresponding population has a normal distribution.

**View Solution:**## Answer to relevant Questions

A gas station attendant would like to estimate p, the proportion of all households that own more than two vehicles. To obtain an estimate, the attendant decides to ask the next 200 gasoline customers how many vehicles their ...Calculating a confidence interval for the proportion requires a minimum sample size. Calculate a confidence interval, using any confidence level of 90% or higher, for the population proportion for each of the following. a. n ...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 ...Lazurus Steel Corporation produces iron rods that are supposed to be 36 inches long. The machine that makes these rods does not produce each rod exactly 36 inches long. The lengths of the rods vary slightly. It is known that ...You are interested in estimating the mean age of cars owned by all people in the United States. Briefly explain the procedure you will follow to conduct this study. Collect the required data on a sample of 30 or more cars ...Post your question