Question

If the mean and variance of a binomial distribution are $\frac{15}{4}$ and $\frac{15}{16}$. The number of trials is

• A. $5$
• B. $2$
• C. $4$
• D. $6$

Answer 1

The correct option is A $5$

$Mean=np$
$=\frac{15}{4}$
$Variance$
$=np(1-p)$ $=\frac{15}{16}$

Hence $\frac{15}{16}=\frac{15}{4}(1-p)$
$p=\frac{3}{4}$
Therefore $n=5$