I would appreciate some assistance is getting this challenge debunked :

2. In an effort to boost sales, Heineken decided to use a well-placed life-size picture of a celebrity in supermarkets. a) If it is believed that such initiatives have increased sales in the past by 45 bottles per week with a standard deviation of 12 bottles, what is the probability that i. in a sample of 20 supermarkets, the increase in sales would have been less than 30 bottles per week? ii. one supermarket's weekly sales would have increased by more than 35 bottles? b) Create a 90% confidence interval for the average increase in bottles sold if a sample of 25 supermarkets yielded an average increase of 42 bottles per week. c) What is the margin of error for this interval? d) The marketing division of Heineken, believes that given the celebrity being used, sales should increase by more than 50 bottles. If a sample of 36 supermarkets had an average increase of 45 bottles, how would you respond to the marketing division's claim? Note: the standard deviation given in a) should be also used for all other parts of this