Question

A supervisor records the repair cost for 14 randomly selected refrigerators. A sample mean of $67.58 and standard deviation of $24.65 are subsequently computed. Determine the 90% confidence interval for the mean repair cost for the refrigerators. Assume the population is approximately normal. Step 1 of 2: Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.

Answer 1

To find the critical value for constructing a 90% confidence interval, use the z-value associated with a 90% confidence level, which is approximately 1.645.

Step-by-step explanation:

To find the critical value for constructing a 90% confidence interval, we can use the z-value associated with a 90% confidence level. The z-value can be found using a standard normal distribution table or a calculator. For a 90% confidence level, the z-value is approximately 1.645. Therefore, the critical value to be used in constructing the confidence interval is 1.645.