I am trying to calculate the mean from two values, the 50th and 95th percentiles of a log normal distribution using R. Those values are 0.3 for the 50th percentile and 9.1 for the 95th percentile.
Actually, I am trying to apply the method used in How to calculate a mean and standard deviation for a lognormal distribution using 2 percentiles, but I don't understand how the mean can be calculated with that mean = mean(ln((42 \ 666))). I don't understand that sign . I tried with this sign / but the results were different.
How to determinate the mean those two percentiles by using R ?
