8. It is known that lemmings (small rodent like creatures) have a mean body weight of 63.5 grams with a standard deviation of 12.2 grams. If the weights are distributed normally, calculate the following: (a) The probability that a randomly chosen lemming will have a body weight of 54 grams or less. (b) The probability that a random sample of 15 lemmings will have an average body weight of 54 grams or less. (c) Explain the difference in the two probabilities calculated in parts (a) and (b). (d) If the sample size in part (b) was doubled, how would the probability change