We have seen that if $Y$ has a binomial distribution with parameters $n$ and $p$, then $Y / n$ is an unbiased estimator of $p .$ To estimate the variance of $Y$, we generally use $n(Y / n)(1-Y / n)$.
a. Show that the suggested estimator is a biased estimator of $V(Y)$
b. Modify $n(Y / n)(1-Y / n)$ slightly to form an unbiased estimator of $V(Y)$