# How can I calculate the mean and standard deviation given three percentiles using Matlab?

I have the percentiles of 3 values. The percentiles are 5th, 50th and 95th. The values respectively are 340, 365 and 385. How can I find the median and the standard deviation given that data follow a normal distribution?

I used qnorm(0.05) in R to estimate the number of standard deviations the 5th percentile is from the mean, given a normal distribution. It's 1.644854. Good luck!
• R is software that can be used (among others) statistical analyses. link You could have looked that 1.64 up in a table as well, but I had an R session open anyway :-) saw your edit If 340 is 1.64 sd away from the mean (in the normal distribution very similar to the median), that means: sd = (365 - 340) / 1.644854 = 15.19892. – Jasper Dec 24 '15 at 8:32