In a binomial distribution , the probability of getting success is $\frac{1}{5}$ and standard deviation is 4. Then, its mean is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 20
In a Binomial Distribution, the standard deviation is
$σ=\sqrt{np(1-p)}$
$⇒4=\sqrt{n×0.2×(1-0.2)}$
$⇒16=n×0.2×0.8$
$⇒n=\frac{16}{0.2×0.8}=100$
$∴μ=np=0.2×100=20$