I have a code:

 x1=rnorm(100,-10,1)
 sum(x1>quantile(x1,0.05))/length(x1)
 

I would like to ask someone from the forum to explain to me what exactly the second line of code does. Thank you in advance for your help.

CodePudding user response：

x1 is 100 normally distributed #s from a population with mean of -10.

quantile(x1,0.05) identifies the 5th percentile of that vector.

x1>quantile(x1,0.05) tests each element in x1 to see if it's more than that 5th percentile, outputting TRUE (aka 1) if so, so its sum is a count of elements larger than the 5th percentile.

Finally, it's divided by the number of elements in x1: 100. So we're checking what percentage of the values are more than the 5th percentile. I'd expect 95%.