A study conducted by a train transportation authority with a random sample of 300 passengers shows that a customer had to wait on an average of 10.3 minutes with a standard deviation of 6.2 minutes to buy his or her ticket. It is suspected that the actual average waiting time is not 10.3 minutes. Use the 0.05 significance level.

a). State the null hypothesis and the alternative hypothesis. (5 marks)

b). What is the probability of a Type I error? (5 marks)

c). Give the formula for the test statistic. (5 marks)

d). State the decision rule. (5 marks)

e). A random sample of 184 customers of the 300 customers showed a mean of 9.3. Shall we reject the hypothesis that the population mean is 10.3? State your conclusion.