# stats_cdf_exponential

(PECL stats >= 1.0.0)

stats_cdf_exponential — Calculates any one parameter of the exponential distribution given values for the others

### Descripción

stats_cdf_exponential(float `$par1`, float `$par2`, int `$which`): float

Returns the cumulative distribution function, its inverse, or one of its parameters, of the exponential distribution. The kind of the return value and parameters (`par1` and `par2`) are determined by `which`.

The following table lists the return value and parameters by `which`. CDF, x, and lambda denotes cumulative distribution function, the value of the random variable, and the rate parameter of the exponential distribution, respectively.

Return value and parameters
`which` | Return value | `par1` | `par2`
--- | --- | --- | ---
1 | CDF | x | lambda
2 | x | CDF | lambda
3 | lambda | x | CDF

### Parámetros

`par1`

  The first parameter

`par2`

  The second parameter

`which`

  The flag to determine what to be calculated

### Valores devueltos

Returns CDF, x, or lambda, determined by `which`.