The average age for licensed drivers in the county is = 40.3 years with a standard

Question:

The average age for licensed drivers in the county is µ = 40.3 years with a standard deviation of σ = 13.2 years.
a. A researcher obtained a random sample of n = 16 parking tickets and computed an average age of
M = 38.9 years for the drivers. Compute the z-score for the sample mean and find the probability of obtaining an average age this young or younger for a random sample of licensed drivers. Is it reasonable to conclude that this set of n = 16 people is a representative sample of licensed drivers?
b. The same researcher obtained a random sample of n = 36 speeding tickets and computed an average age of µ = 36.2 years for the drivers. Compute the z-score for the sample mean and find the probability of obtaining an average age this young or younger for a random sample of licensed drivers. Is it reasonable to conclude that this set of n = 36 people is a representative sample of licensed drivers?