--- Michael McCulloch <[email protected]> wrote:
> For the command below which creates a variable with mean 200 and
> sd==25,
> gen chol = 200+25 * invnorm(uniform())
>
> what does the "invnorm(uniform()))" do?
> I know the uniform() draws a random number with mean 0 and sd==1, but
>
> what about the "invnorm" part?
-invnorm()- is an old name for -invnormal()- which I sometimes still
use because I forget the new name. To quote the helpfile: it "returns
the inverse cumulative standard normal distribution: if normal(z) = p,
then invnormal(p) = z." So this turns the draws from the uniform
distribution into draws from a standard normal distribution, than
multiplying by 25 leads to a standard dev. of 25 and adding 200 leads
to a mean of 200.
-- Maarten
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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