MENU
Question -

In a meeting, 70% of the members favour and 30% oppose a certain proposal. A member is selected at random and we take X = 0 if he opposed, and X = 1 if he is in favour. Find E(X) and Var (X).



Answer -

Given: X = 0 ifmembers oppose, and X = 1 if members are in favour.

P(X = 0) = 30% =30/100 = 0.3

P(X = 1) = 70% =70/100 = 0.7

Hence, the requiredprobability distribution is,

X

0

1

P (X)

0.3

0.7

Therefore E(X) is:

= 0 × 0.3 + 1 × 0.7

⇒ E(X) = 0.7

And E(X2)is:

= (0)2 ×0.3 + (1)2 × 0.7

⇒ E(X2)= 0.7

Then Variance, Var(X)= E(X2) – (E(X))2

= 0.7 – (0.7)2

= 0.7 – 0.49 = 0.21

Comment(S)

Show all Coment

Leave a Comment

Free - Previous Years Question Papers
Any questions? Ask us!
NodeJS Interview Questions Answers
ASP.Net Interview Questions Answers
Interview Questions Answers
×