How can i establish that for each $p \in [0,1] $ if $X_{1},X_{2}...$ are a coin runs to parameter p, with the propability P to cover up the confidence region $R:=\left[\overline{X}_n-\frac{\sqrt{5}}{\sqrt{n}}, \overline{X}_n+\frac{\sqrt{5}}{\sqrt{n}}\right]$ with Chebyshev inequality: $P((\overline{X}_n-EX) \ge c\sigma) \le \frac{1}{c^2}$ not less than .95!
I start with
$=> $ $P((\overline{X}_n-EX) \le c\sigma) \ge 1 - \frac{1}{c^2} \ge 0.95 $
$P(\overline{X}_n-\frac{\sqrt{5}}{\sqrt{n}}\le p \le \overline{X}_n+\frac{\sqrt{5}}{\sqrt{n}}) = 0.95$
$1-\frac{1}{c^2} = 0.95$ $c=2\sqrt{5}$
From here I am stuck...