Question

The length of time for an online grocery delivery service is normally distributed and has a known population standard deviation of 11 minutes and an unknown population mean. A random sample of 15 deliveries is taken and gives a sample mean of 101 minutes. Use a calculator to find the confidence interval for the population mean with a 98% confidence level. Round the final answer to two decimal places. Provide your answer below: ( , )

Answer 1

n= 15,  =11, = 101, c= 98%

We are using TI-83 calculator to calculate confidence interval

Steps are as follows

1) press button STAT

2) navigate to TEST by using left arow key

3) scroll down to Z Interval and press ENTER

4) insert data as follows and click on CALCULATE

5) thus you ill get answer as follows

Thus we get confidence interval as follows

94.39 <   < 107.61

Answer = ( 94.39 , 107.61)