15) Let x represent the dollar amount spend on supermarket impulse buying in a 10-minute unplanned shopping interval. The mean of this distribution is u=$20 and the standard deviation is o=$7. If we assume the x distribution is approximately normal: a. (1) What is the probability that a randomly selected shopper will spend between $18 and $22? b. (1) Consider a random sample of n = 100 shoppers. What is the probability that X is between $18 and $22? c. (2) State two different ways we know the x distribution from part (b) is normally distributed