The owner of a petrol station wants to study fuel-purchasing habits ofmotorists at his station. A random sample of 60 motorists during a particular week gave the following results:

Amount purchased: x-bar = 42.8 litres, S =11.7litres.

The owner wants to testwhether there is evidence that the mean amount of fuel purchased at his stationis more than 40 litres.

(b)  What is the p-value?                                                                  

        p-value =

0.9656

(e)   Do we need to assume for the analysis in (b) that the amountspurchased follow a normal distribution? Discuss.



主要是(e)，不太懂需要不需要让样本服从正态分布。真心请求大家解答！！先谢过！！