What is the mean of the binomial distribution for which n=20 and p=0.2?

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Answer 1 · 2017-02-07T08:58:47

4

For a binomial distribution

#X~B(n,p)#

the mean is

#" " E(X)=np, " and its variance "Var(X)=np(1-p)#

in this case we have:#" "X~B(,20,0,2)#

so#" " E(X)=20xx0.2=4#

for good measure the variance will be

#Var(X)=20xx0.2xx0.8=3.2#