X=guessing a answer
n=43
p(success)==0.25
q(failure)=1-p=1-0.25=0.75
X~binom(43,0.25)
1.
E(X)=np
E(X)=43*0.25
E(X)=10.75
hence, option(A) 10.75 is correct.
2.
Var(X)=npq=43*0.25*0.75
Var(X)=8.0625
standard deviation==
standard deviation=2.84
hence,option(A) 2.84 is correct.
please rate my answer and comment for doubts.
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