(a) In the 2010 the average amount spent per week on fast food was $24.50. It is widely suspected that people today are more health conscious. The manager of a fast food outlet records the amount spent for 9 weeks. 16 14 19 26 24 24 16 10 19 Assuming that the amounts are normally distributed with a known population standard deviation of $6.60, can we conclude that the mean amount spent per week on fast food has decreased? Use a = 0.01