g If annual incomes for a population are normally distributed with a mean income of $67,000 and a standard deviation of $4,200, a) What is the probability that a randomly selected student earns more than $67,000? b) What’s the probability that a randomly selected student earns between $65,000 and $70,000? c) What’s the probability that the sample average earnings of 20 people is less than $60,000?