Variance of a Coin Indicator

Bernoulli variance is $p(1-p)$.

$p=1/2$.

1. 1. Compute

   $$\frac{1}{2}\cdot \frac{1}{2}=\frac{1}{4}$$

2. 2. Key idea

   Bernoulli variance peaks at $p=1/2$.

Answer: 1/4