7.3 Log-Normal Distribution

R script for log-normal distribution

Dlnorm

## function (x, mu = 0, sig = 1) 
## {
##     if (sig <= 0) {
##         warning("bad sigma for a log-normal distribution")
##         return(NULL)
##     }
##     if (x < 0) {
##         warning("bad x for a log-normal distribution")
##         return(NULL)
##     }
##     if (x == 0) 
##         return(0)
##     return(0.398942280401433/(sig * x) * exp(-0.5 * (log(x) - 
##         mu) * (log(x) - mu)/sig/sig))
## }
## <bytecode: 0x000001e2abf6fb38>
## <environment: namespace:math>

Plnorm

## function (x, mu = 0, sig = 1) 
## {
##     if (sig <= 0) {
##         warning("bad sigma for a log-normal distribution")
##         return(NULL)
##     }
##     if (x < 0) {
##         warning("bad x for a log-normal distribution")
##         return(NULL)
##     }
##     if (x == 0) 
##         return(0)
##     return(0.5 * erfc(-0.707106781186548 * (log(x) - mu)/sig))
## }
## <bytecode: 0x000001e2abebeea0>
## <environment: namespace:math>

Qlnorm

## function (p, mu = 0, sig = 1) 
## {
##     if (sig <= 0) {
##         warning("bad sigma for a log-normal distribution")
##         return(NULL)
##     }
##     if (p <= 0 | p >= 1) {
##         warning("bad p ifor a log-normal distribution")
##         return(NULL)
##     }
##     return(exp(-1.4142135623731 * sig * inverfc(2 * p) + mu))
## }
## <bytecode: 0x000001e2abdfc4a0>
## <environment: namespace:math>