# Question

A company services home air conditioners. It has been found that times for service calls follow a Normal distribution with a mean of 60 minutes and a standard deviation of 10 minutes. A random sample of four service calls was taken.

a. What is the probability that the sample mean service time is more than 65 minutes?

b. The probability is 0.10 that the sample mean service time is less than how many minutes?

c. The probability is 0.10 that the sample standard deviation of service times is more than how many minutes?

d. The probability is 0.10 that the sample standard deviation of service times is less than how many minutes?

e. What is the probability that more than two of these calls take more than 65 minutes?

a. What is the probability that the sample mean service time is more than 65 minutes?

b. The probability is 0.10 that the sample mean service time is less than how many minutes?

c. The probability is 0.10 that the sample standard deviation of service times is more than how many minutes?

d. The probability is 0.10 that the sample standard deviation of service times is less than how many minutes?

e. What is the probability that more than two of these calls take more than 65 minutes?

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