The probability is 0.35 that a traffic fatality involves an intoxicated oralcohol-impaired driver or nonoccupant. In seven trafficfatalities, find the probability that thenumber, Y, which involve an intoxicated oralcohol-impaired driver or nonoccupant is

a. exactlythree; at leastthree; at most three.

b. between two and four, inclusive.

c. Find and interpret the mean of the random variable Y.

d. Obtain the standard deviation of Y.

a. The probability that exactly three traffic fatalities involve an intoxicated oralcohol-impaired driver or nonoccupant is 0.26730.2673.

(Round to four decimal places asneeded.)

The probability that at least three traffic fatalities involve an intoxicated oralcohol-impaired driver or nonoccupant is 0.79870.7987.

(Round to four decimal places asneeded.)

The probability that at most three traffic fatalities involve an intoxicated oralcohol-impaired driver or nonoccupant is nothing.

(Round to four decimal places asneeded.)

b. The probability that between two and four trafficfatalities, inclusive, involve an intoxicated oralcohol-impaired driver or nonoccupant is nothing.

(Round to four decimal places asneeded.)

c. The mean of Y is

Choose the correct interpretation of the mean below.

A.

In every seven trafficfatalities, exactly this many will involve an intoxicated oralcohol-impaired driver or nonoccupant.

B.

Onaverage, of seven trafficfatalities, this many will involve an intoxicated oralcohol-impaired driver or nonoccupant.

C.

Onaverage, of this many trafficfatalities, 1 will involve an intoxicated oralcohol-impaired driver or nonoccupant.

d. The standard deviation of Y is