With individual lines at its various windows, a post office finds the standard deviation for normally distributed waiting times for customers on Friday afternoon is 7.2 minutes. The post office...

With individual lines at its various windows, a post office finds the standard deviation for normally distributed waiting times for customers on Friday afternoon is 7.2 minutes. The post office experiments with a single, main waiting line and finds that a random sample of 25 customers, the waiting times for customers have a standard deviation of 3.5 minutes.

with a significance level of 5% , test the claim that a single line causes lower variation among waiting times(shorter waiting times) for customers.

a. Hypothesis

b. Test statistics

c. P value/critical value

d.decision on null hypothesis

e. Conclusion