R.QNORM(p,mu,sigma,lower_tail,log_p)
p: probability
mu: mean of the distribution
sigma: standard deviation of the distribution
lower_tail: if true (the default), the lower tail of the distribution is considered
log_p: if true, log of the probability is used
This function returns the probability quantile function, i.e., the inverse of the cumulative distribution function, of the normal distribution.