In R-studio, there are many commands of Gumbel package. Arguments are also different. I`m asking about the alpha parameter of the Copula which must be greater than 1. If this is the one used to plot the probability paper, how can I choose the value of alpha?

The following code is the probability paper for normal (Gaussian) distribution:

qdb<-read.csv2(file = "peakQ.csv", sep = ",")

qdf<-data.frame(Q=sort(qdb$Q.peak))

id<- 1:length(qdf$Q)

Fx <- id/(1+length(id)) plot(qdf$Q, Fx, xlab = "Q(m3/s)", ylab = "CDF")

iphiFx <-qnorm(Fx) plot(qdf$Q, iphiFx, xlab = "Q(m3/s)", ylab = "Inverse phi [Fx]")

However I`d like to know what equivalent command to qnorm() of gumbel, and what are the input arguments.

Many thanks