Question: According to international Mass Retail Assn., girls aged 15 to 17 spend an average of $45.00 on shopping trips in a month. Assume that the amounts have a standard deviation of $12.50. Use z-scores to address the following:

If a sample of 45 girls in that age category is randomly selected, what is the probability that their mean monthly shopping expense is

a) over $48.00?

b) less than $40.00?

c) Describe the sampling distribution of the means for samples of size 45 in this problem. is a mean of $50.00 unlikely for this sample. Explain reasoning.