Question

A simple random sample of kitchen toasters is to be taken to determine the mean operational lifetime in hours. Find the sample size needed so that a 98% confidence interval for the population mean lifetime will have a margin of error of 4.

Answer 1

To find the sample size needed for a 98% confidence interval with a margin of error of 4, a formula can be used. However, additional information is needed.

Step-by-step explanation:

To find the sample size needed in order to have a 98% confidence interval for the population mean lifetime with a margin of error of 4, we can use the formula:

Sample size = (Z * standard deviation / margin of error) ^ 2

Where Z is the z-score corresponding to the desired level of confidence. Since we want a 98% confidence level, Z is the z-score corresponding to a 99% confidence level, which is approximately 2.33.

Given that the margin of error is 4 and the standard deviation is unknown, we cannot calculate the exact sample size without additional information.