Question

In a binomial distribution X denotes a random variable so that it's mean and variance are 4 and 2 respectively then P(X=1) equal to

Answer 1

Answer:

Given mean=4

Variance=2

∴np=4

and npq=2

∴4q=2,q=42=21

p=1−q=21

∴n(1/2)=4;n=8

Thus 

p(X=1)=8C1(21)(21)7

=8(21)8=2568=321

Answer 2

Answer:

Answer:

Given mean=4

Variance=2

∴np=4

and npq=2

∴4q=2,q=42=21

p=1−q=21

∴n(1/2)=4;n=8

Thus 

p(X=1)=8C1(21)(21)7

=8(21)8=2568=321