## Beta Type II Distribution

A continuous random variable $X$ is said to have a beta type II distribution with parameters $\alpha$ and $\beta$ if its p.d.f. is given by
```
$$
\begin{equation*}
f(x)=\left\{
\begin{array}{ll}
\frac{1}{B(\alpha,\beta)}\cdot\frac{x^{\alpha-1}}{(1+x)^{\alpha+\beta}}, & \hbox{$0\leq x\leq\infty$;} \\
0, & \hbox{Otherwise.}
\end{array}
\right.
\end{equation*}
$$
```

where,

`$B(\alpha,\beta) =\frac{\Gamma \alpha \Gamma \beta}{\Gamma (\alpha+\beta)}=\int_0^1 x^{\alpha-1}(1-x)^{\beta-1}\; dx$`

is a beta function and`$\Gamma \alpha$`

is a gamma function.

## Mean of Beta Type II Distribution

The mean of beta type II distribution is

### $E(X) = \dfrac{\alpha}{\beta-1}$.

## Variance of Beta Type II Distribution

The variance of beta type II distribution is

### $V(X) = \dfrac{\alpha(\alpha+\beta-1)}{(\beta-1)^2(\beta-2)}$.

## Harmonic Mean of Beta Type II Distribution

The harmonic mean of beta type II distribution is

### $H = \dfrac{\alpha-1}{\beta}$.

## Mode of Beta Type-II Distribution

The mode of beta type II distribution is