1. 85 recent graduates want to be certified engineers. On average, it took them 22 months, with a standard deviation of five months, to pass the Texas exam.

Construct a 90% confidence interval for the sample mean of the prep time.

( , )

Round your answer to two decimal digits.

Construct a 95% confidence interval for the sample mean of the prep time.

( , )

Round your answer to two decimal digits.

2. A machine used to fill half-gallon-paint containers is regulated so that the amount of paint dispensed has a mean of 64 ounces and a standard deviation of 0.12 ounce.

You randomly select 50 containers and carefully measure the contents. The sample mean of the containers is 63.03 ounces.

Use a 98% confidence interval to test whether the machine needs to be reset.

The confidence interval is: ( , )

Round your answer to two decimal digits.

Do you conclude that the machine needs to be reset? (Yes, No)

Note: If 64 belongs to the confidence interval, then the machine is working properly. If 64 does not belong to the confidence interval, then the machine is not working properly, so it needs to be reset.