stats_cdf_beta

(PECL stats >= 1.0.0)

stats_cdf_beta — Calculates any one parameter of the beta distribution given values for the others

说明

stats_cdf_beta(
    float $par1,
    float $par2,
    float $par3,
    int $which
): float

Returns the cumulative distribution function, its inverse, or one of its parameters, of the beta 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, alpha, and beta denotes cumulative distribution function, the value of the random variable, and shape parameters of the beta distribution, respectively.

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

参数

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

返回值

Returns CDF, x, alpha, or beta, determined by which.

add a note

User Contributed Notes 2 notes

down

Anonymous ¶

14 years ago


Additional Notes, taken from source.
 WHICH --> Integer indicating which of the next four argument
       values is to be calculated from the others.
     Legal range: 1..4
     iwhich = 1 : Calculate P and Q from X,Y,A and B
     iwhich = 2 : Calculate X and Y from P,Q,A and B
     iwhich = 3 : Calculate A from P,Q,X,Y and B
     iwhich = 4 : Calculate B from P,Q,X,Y and A
     
     P <--> The integral from 0 to X of the chi-square
     distribution.
     Input range: [0, 1].
     
     Q <--> 1-P.
     Input range: [0, 1].
     P + Q = 1.0.
     
     X <--> Upper limit of integration of beta density.
     Input range: [0,1].
     Search range: [0,1]
     
     Y <--> 1-X.
     Input range: [0,1].
     Search range: [0,1]
     X + Y = 1.0.
     
     A <--> The first parameter of the beta density.
     Input range: (0, +infinity).
     Search range: [1D-100,1D100]
     
     B <--> The second parameter of the beta density.
     Input range: (0, +infinity).
     Search range: [1D-100,1D100]

down

-1

n15m0_jk ¶

8 years ago


Decided to dive into the source code and provide a simple explanation:

Parameters:
int $which - Select which parameter to use in the CDF Binomial calculation, based on what the prior 3 parameters are.

where $which is 4:
$arg1 = p
$arg2 = sn
$arg3 = xn
returns pr

$which = 3
$arg1 = p
$arg2 = sn
$arg3 = pr
returns xn

$which = 2
$arg1 = p
$arg2 = xn
$arg3 = pr
returns sn

$which = 1
$arg1 = sn
$arg2 = xn
$arg3 = pr
returns p

add a note