Question

The mean and variance of Binomial Distribution are 6, 4. Then the parameters of the distribution are

• A. $12,\frac{1}{2}$
• B. $9,\frac{2}{3}$
• C. $10,\frac{3}{5}$
• D. $18,\frac{1}{3}$

Answer 1

The correct option is D $18,\frac{1}{3}$

Mean $=np$
$=6$
Variance $=np(1-p)$
$=4$
Therefore $4=6(1-p)$
$1-p=\frac{2}{3}$

$p=\frac{1}{3}$
Therefore
$n=6\left(3\right)$
$=18$