WEIBULL(x,alpha,beta,cumulative)
WEIBULL . @cumulative TRUE (), 1 - exp (-(@x/@beta)^@alpha), (@alpha/@beta^@alpha) * @x^(@alpha-1) * exp(-(@x/@beta^@alpha)).
@x < 0, WEIBULL #NUM!. @alpha <= 0 @beta <= 0, WEIBULL #NUM!.
Excel.
WEIBULL(3,2,4,0) 0.213668559.
POISSON.