Using historical records, the personnel manager of a plant has determined the probability distribution of X, the number of employees absent per day. It is x 0 1 2 3 4 5 6 7 P (x) .005 .025 .310 .340 .220 .080 .019 .001

a. Find the following probabilities.

P(X  5)

P(X  4)

b. Calculate the mean of the population.

c. Calculate the standard deviation of the population.