A large population of seeds of the princess beans Phaseotus vulgaris is to be sampled. The weight of the seeds in the population follow a normal distribution with mean mu = 500 mg, and standard deviation sigma = 120 mg. What percentage of seeds have a weight 520 mg or more? Suppose now that a random sample of four seeds is to be weighted. What is the probability that the mean weight of the four seeds will be greater than 550 mg? We select 45 seeds at random. What is the probability that the average weight of these 45 seeds will be between 480 mg and 520 mg? Do the answers of parts (b) and (c) change if the weight of a seed is not normally distributed? Explain why or why not in each case.