问题
I have read the documentation on qnorm() but could not really understand what it does. Can you please answer in detail what qnorm() does?
note-Please excuse me for asking such a simple question. I am a beginner at R.
回答1:
The function qnorm() aims to find the boundary value, A in P(X < A), given the probability P.
For example, suppose you want to find the 85th percentile of a normal distribution whose mean is 70 and whose standard deviation is 3. Then you ask for:
qnorm(0.85,mean=70,sd=3)
[1] 73.1093
From https://cran.r-project.org/web/packages/tigerstats/vignettes/qnorm.html
回答2:
"The idea behind qnorm is that you give it a probability, and it returns the number whose cumulative distribution matches the probability. For example, if you have a normally distributed random variable with mean zero and standard deviation one, then if you give the function a probability it returns the associated Z-score"
from http://www.cyclismo.org/tutorial/R/probability.html
You can further refer to the above link to read up more on the same.
来源：https://stackoverflow.com/questions/37301228/function-of-qnorm-in-r