Question

a researcher records the repair cost for 4 randomly selected refrigerators. a sample mean of $85.03 and standard deviation of $22.34 are subsequently computed. determine the 80% 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

The critical value for the 80% confidence interval is 1.281.

Step-by-step explanation:

To find the critical value for a given confidence interval, we need to consult a standard normal distribution table or use a calculator with a normal distribution function.

Since the confidence level is 80%, we want to look for the z-value that corresponds to an area of 0.1 on both tails of the distribution.

From the standard normal distribution table, the z-value for an area of 0.1 in each tail is approximately 1.281.

Therefore, the critical value to be used in constructing the confidence interval is 1.281.