The probability is

0.3

0.3 that a traffic fatality involves an intoxicated or alcohol-impaired driver or nonoccupant. In

seven

seven traffic fatalities, find the probability that the number, Y, which involve an intoxicated or alcohol-impaired driver or nonoccupant is

a. exactly three; at least three; at most three.

b. between

two

two and

four

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 or alcohol-impaired driver or nonoccupant is

nothing

.

(Round to four decimal places as needed.)

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

nothing

.

(Round to four decimal places as needed.)

The probability that at most three traffic fatalities involve an intoxicated or alcohol-impaired driver or nonoccupant is

nothing

.

(Round to four decimal places as needed.)

b. The probability that between

two

two and

four

four traffic fatalities, inclusive, involve an intoxicated or alcohol-impaired driver or nonoccupant is

nothing

.

(Round to four decimal places as needed.)

c. The mean of Y is

nothing

.

Choose the correct interpretation of the mean below.

A.

In every

seven

seven traffic fatalities, exactly this many will involve an intoxicated or alcohol-impaired driver or nonoccupant.

B.

On average, of this many traffic fatalities, 1 will involve an intoxicated or alcohol-impaired driver or nonoccupant.

C.

On average, of

seven

seven traffic fatalities, this many will involve an intoxicated or alcohol-impaired driver or nonoccupant.

d. The standard deviation of Y is

nothing

. (Round to two decimal places as needed.)