Question

If the probability of defective bolts is 0.1, find the mean and standard deviation for the distribution of defective bolts in a total of 500 bolts.

Answer 1

We have,

$n=500$ and $p=0.1$

Therefore, Mean = $np=500\times 0.1=50$

And, $S.D.=\sqrt{Variance}=\sqrt{npq}=\sqrt{500\times 0.1\times 0.9}=6.71$