PHP Manual: Calculates any one parameter of the gamma distribution given values for the others

Description

float stats_cdf_gamma(
    float $par1,
    float $par2,
    float $par3,
    int $which
)

Returns the cumulative distribution function, its inverse, or one of its parameters, of the gamma distribution. The kind of the return value and parameters (par1, par2, and par3) are determined by which.

The following table lists the return value and parameters by which. CDF, x, k, and theta denotes cumulative distribution function, the value of the random variable, and the shape and the scale parameter of the gamma distribution, respectively.

**Return value and parameters**
`which`	Return value	`par1`	`par2`	`par3`
1	CDF	x	k	theta
2	x	CDF	k	theta
3	k	x	CDF	theta
4	theta	x	CDF	k

Parameters

par1: The first parameter
par2: The second parameter
par3: The third parameter
which: The flag to determine what to be calculated

Return Values

Returns CDF, x, k, or theta, determined by which.