Gamma Distribution

Parameters

Domain

Three-Parameter Gamma Distribution

Probability Density Function

Cumulative Distribution Function

Two-Parameter Gamma Distribution

Probability Density Function

Cumulative Distribution Function

where is the Gamma Function,  and is the Incomplete Gamma Function.

Worksheet and VBA Functions

The following worksheet and VBA functions are available for this distribution:

Description	VBA Functions	Worksheet Functions
Distribution Fitting	-	=DistFit("Gamma";Data;[Options]1)
Probability Density Function	GammaPdf(x,alpha,beta,[gamma])	=GammaPdf(alpha;beta;[gamma]) =DistPdf("Gamma(alpha;beta;[gamma])";x)
Cumulative Distribution Function	GammaCdf(x,alpha,beta,[gamma])	=GammaCdf(alpha;beta;[gamma]) =DistCdf("Gamma(alpha;beta;[gamma])";x)
Survival Function	GammaSurv(x,alpha,beta,[gamma])	=DistSurv("Gamma(alpha;beta;[gamma])";x)
Hazard Function	GammaHaz(x,alpha,beta,[gamma])	=GammaHaz(alpha;beta;[gamma]) =DistHaz("Gamma(alpha;beta;[gamma])";x)
Cumulative Hazard Function	GammaCumHaz(x,alpha,beta,[gamma])	=DistCumHaz("Gamma(alpha;beta;[gamma])";x)
Inverse CDF (Quantile Function)	GammaInv(P,alpha,beta,[gamma])	=GammaInv(alpha;beta;[gamma]) =DistInv("Gamma(alpha;beta;[gamma])";P)
Random Numbers	GammaRand(alpha,beta,[gamma])	=GammaRand(alpha;beta;[gamma]) =DistRand("Gamma(alpha;beta;[gamma])")
Mode	GammaMode(alpha,beta,[gamma])	=DistMode("Gamma(alpha;beta;[gamma])")
Mean	GammaMean(alpha,beta,[gamma])	=GammaMean(alpha;beta;[gamma]) =DistMean("Gamma(alpha;beta;[gamma])")
Variance	GammaVar(alpha,beta,[gamma])	=GammaVar(alpha;beta;[gamma]) =DistVar("Gamma(alpha;beta;[gamma])")
Standard Deviation	GammaStdev(alpha,beta,[gamma])	=GammaStdev(alpha;beta;[gamma]) =DistStdev("Gamma(alpha;beta;[gamma])")
Skewness	GammaSkew(alpha,beta,[gamma])	=DistSkew("Gamma(alpha;beta;[gamma])")
(Excess) Kurtosis	GammaKurt(alpha,beta,[gamma])	=DistKurt("Gamma(alpha;beta;[gamma])")

1. The Options parameter is optional. Possible options: "gamma=value"  (example: "gamma=0")
2. The gamma parameter is optional (the default value is 0).