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

Description

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

Returns the cumulative distribution function, its inverse, or one of its parameters, of the negative binomial 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, r, and p denotes cumulative distribution function, the number of failure, the number of success, and the success rate for each trial, respectively.

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

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, r, or p, determined by which.