The waiting time for a service is normally distributed. One wants to estimate the average waiting time for the service. Data of a sample of 11 services were collected. The sample mean is 2.20 minutes, and the sample standard deviation is 0.35 minutes. Determine a 95% confidence interval.

1) For the confidence interval to be valid, it is necessary that test scores of the business students be normally distributed. Give your reason.

2) Calculate the 95% confidence interval for the mean score of business students.

Lower limit

Upper limit