Set sum random sample

Question

So this seems like a really simple question to me, but I can't seem to figure it out. I'm using R and I'm trying to generate a random sample, where the generated sample all sums to a set number.

You do know about the Central Limit Theorem, right? – C8H10N4O2 Jul 01 '15 at 13:45 — C8H10N4O2, Jul 01 '15 at 13:45

score 1 · Answer 1 · answered Jul 01 '15 at 13:54

Here's an approach to consider. Generate some random numbers:

n   = 10
x <- runif(n) # or rnorm, rpois, whatever you want to use

And then scale() them to get the sum you want.

tot = 100 # this is the sum you want
x <- scale(x, center=FALSE, scale=sum(x)/tot)
all.equal(sum(x), tot) #TRUE

Set sum random sample

1 Answers1