The population mean waiting time to check out of a supermarket has been 10.73 minutes. Recently, in an effort to reduce the waiting time, the supermarket has experimented with a system in which there is single waiting line with multiple server checkouts. A sample of 100 customers was selected, and their mean waiting time to check out was 9.52 minutes, with a SD of 5.8 minutes.
a. At the 0.05 level of significance, is there evidence to suggest that the population mean waiting time to check out is less than 10.73 minutes?
b. What is the p-value?