In the United States, the year each coin was minted is printed on the coin. To find the age of a coin, simply substract the current year from the year printed on the coin. The ages of circulating pennies are right skewed. In other words, most circulatin pennies were minted relatively recently, and extremely old pennies are rare. Assume the ages of circulatin pennies have a mean of 12.2 years and a standard deviation of 9.9 years.
a) What is the probability that the randomly selected penny is over 5 years old? (If this cannoct be calculated from the information given, explain why)
b) What is the probability that a random sample of 40 circulating pennies has a mean less than 10 years? (If this cannot be calculated from the information given, explain why)