A local pizza parlor claims to deliver all pizzas within 30 minutes. A group of students carried out a study and had 100 pizzas delivered over the course of the semester and found an average delivery time of 45 minutes with a standard deviation of 7 minutes. Which of the following is the correct set of hypotheses for testing if the average delivery time was different than the claim of 30 minutes? A. H0 : xbar = 30 vs HA : xbar not= 30
B. H0 : mu = 45 vs HA: mu not= 45
C. H0: xbar = 45 vs Ha: xbar not= 45
D. H0: mu = 30 vs HA: mu not= 30