Question

A dice is thrown thrice. A success is 1 or 6 in a throw. Find the mean and variance of the number of successes.

Answer 1

Here,  n =3

\[\text{ p }= \text{ probability of getting } \ 1 \ \text{ or }\ 6 = \frac{1}{3}\]

\[\text{ and }  \text{ q }= 1 - \frac{1}{3} = \frac{2}{3}\]

\[\text{ Mean } = \text{ np }= 1\]

\[\text{ Variance } = \text{ npq }= \frac{2}{3}\]