A brand of salsa comes in jars marked net weight 680 grams. Suppose the actual mean net weight of all jars is 680 grams with a standard deviation of 22.7 grams. Further suppose that the net weights are normally distributed.
a. Determine the probability that a randomly selected jar of this brand of salsa will have a weight less than 660 grams.
b. Determine the probability that 15 randomly selected jars of this brand of salsa will have a mean weight of less than 660 grams.
c. Why are these probabilities not the same?