7.4 Gamma Distribution

R script for gamma distribution

Dgamma

## function (x, alph, bet = 1) 
## {
##     if (alph <= 0 | bet <= 0) {
##         warning("bad alph, bet for a gamma distribution")
##         return(NULL)
##     }
##     if (x <= 0) {
##         warning("bad x for a gamma distribution")
##         return(NULL)
##     }
##     return(exp(-bet * x + (alph - 1) * log(x) + alph * log(bet) - 
##         gammln(alph)))
## }
## <bytecode: 0x000001e2a475f018>
## <environment: namespace:math>

Pgamma

## function (x, alph, bet = 1) 
## {
##     if (alph <= 0 | bet <= 0) {
##         warning("bad alph, bet for a gamma distribution")
##         return(NULL)
##     }
##     if (x <= 0) {
##         warning("bad x for a gamma distribution")
##         return(NULL)
##     }
##     return(gammp(alph, bet * x))
## }
## <bytecode: 0x000001e2a45cc680>
## <environment: namespace:math>

Qgamma

## function (p, alph, bet = 1) 
## {
##     if (alph <= 0 | bet <= 0) {
##         warning("bad alph, bet for a gamma distribution")
##         return(NULL)
##     }
##     if (p < 0 | p >= 1) {
##         warning("bad p for a gamma distribution")
##         return(NULL)
##     }
##     return(invgammp(p, alph)/bet)
## }
## <bytecode: 0x000001e2a44a7470>
## <environment: namespace:math>