SOLUTION: hello, i needed help to get this answer, im lost trying to get the correct answer? . The National Safety Council publishes information about automobiles accidents in Accidents

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Question 1088258: hello, i needed help to get this answer, im lost trying to get the correct answer?
. The National Safety Council publishes information about automobiles accidents in Accidents
Facts. According to that document, the probability is 3/5 that a traffic fatality involves as
intoxication or alcohol-impaired driver or non-occupant. In eight traffic fatalities, find the
probability that the number, Y, which involve an intoxicated or alcohol-impaired driver or nonoccupant
is
a. Exactly five;
b. at least five;
c. at most five
d. Between two and four, inclusive
e. Find the mean
f. Find the standard deviation of Y

Answer by htmentor(1343) About Me  (Show Source):
You can put this solution on YOUR website!
This is a binomial probability problem involving 8 trials, in which the probability of a "success" is 3/5.
In general, the probability of x successes out of n tries is:
P(x)=n!/(x!(n−x)!)p^x(1−p)^(n−x)
The mean of a binomial distribution is just n*p and the standard deviation is sqrt(n*p(1-p)
a. P(5) = 8!/(5!*3!)*0.6^5*0.4^3 = 0.2787
I will leave it as an exercise to compute the other values...