Question

A symmetrical die is thrown four times and getting a multiple of $2$ is considered to be a success. Then the correct option(s) among the following is/are

• A. mean of success $=1$
• B. mean of success $=2$
• C. variance of success $=1$
• D. variance of success $=2$

Answer 1

Answer: (B), (C)

variance of success $=1$

Given : $n=4,p=\frac{3}{6}=\frac{1}{2},q=\frac{1}{2}$
So, mean $=np=4\times \frac{1}{2}=2$
variance $=npq=4\times \frac{1}{2}\frac{1}{2}=1$