The number of ships to arrive at the harbor on any given day is random variable represented by x. The probability distribution of x is as follows. (Provide your answers correct to two decimal places.)
x 10 11 12 13 14
P(x) 0.39 0.06 0.06 0.11 0.38
(a) Determine the mean of the number of ships that arrive at a harbor on a given day.
(b) Determine the standard deviation, ?, of the number of ships that arrive at a harbor on a given day.