1. The mean annual US household income is $72,641. Suppose that the standard deviation is $30,000. a. Find the probability that
a household chosen at random has an income greater than $100,000. b. Find the probability that a group of 5 households, chosen at random, have an average income greater than $100,000. c. Find the probability that a group of 10 households, chosen at random, have an average income greater than $100,000.