11 percent of people in a city eligible to donate blood actu

11 percent of people in a city eligible to donate blood actually do. You randomly select four eligible blood donors and ask them if they donate blood. Complete parts (a) through (d) below.

(a) Find the mean of the binomial distribution.

(b) Find the variance of the binomial distribution.

(c) Find the standard deviation of the binomial distribution.

Solution

a) The mean of the binomial distribution is np = 4 (0.11) =0.44

b) The varaince of Binomial distribution is np(1-p)= 4(0.11)(0.89)=0.3916

c) Since the standard deviation is the positive root of the varaince

Hence standard deviation is 0.6258