Twentyeight percent of people in a city eligible to donate b

Twenty-eight percent of people in a city eligible to donate blood actually do. You randomly select four eligible donors and ask them if they donate blood. Complete parts (a) through (d) below. A-C round to the nearest one hundreth. D round two two decimal places

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

D) On the average ___ eligible adult(s) out of every 4 gives blood. The standard deviation is ____, so in most samples four eligible adults, the number of adults who donate blood would differ from the average no more than ___.

Solution

A)

mean = n* p = 4 * 0.28 = 1.12

B)

Varience = n*p*q = 4 * 0.28 * 0.72 = 0.8064

C)

sd = sqrt(V) = sqrt(0.8064) = 0.89799

D)

On the average 1.12 eligible adult(s) out of every 4 gives blood. The standard deviation is 0.89799, so in most samples four eligible adults, the number of adults who donate blood would differ from the average no more than 0.89799