topic Re: How to draw a standard normal denstity curve in Graphics Programming

How to draw a standard normal denstity curve

lueryy2000 — Tue, 19 Apr 2011 14:10:26 GMT

Hi all,

I was trying to draw a standard normal density curve using probnorm function. But instead of curvy it is spiky around zero. So is there any way to do it?

Thank you,
Lu

Re: How to draw a standard normal denstity curve

ballardw — Wed, 20 Apr 2011 21:18:01 GMT

It might help to show what you've attempted.

Re: How to draw a standard normal denstity curve

Ksharp — Thu, 21 Apr 2011 07:36:08 GMT

how about it:
[pre]
data normal;
do i=1 to 10000 ;
normal=rand('normal',0,1);
output;
end;
run;
proc univariate data=normal ;
histogram normal/normal;
run;
[/pre]

Ksharp

Re: How to draw a standard normal denstity curve

lueryy2000 — Thu, 21 Apr 2011 14:58:51 GMT

This is the code I used. It only generate the standard normal pdf alone, which is what i want. But you can see it is spiky instead of curvy around zero. Do you know it there better way to do it?

data try;
do z = -5 to 5 by 0.001;
if z gt 0 then pdf = 1- probnorm(z);
else pdf = probnorm(z);
output;
end;
run;

proc gplot data=try;
plot pdf*z ;
run;

Many thanks,
Lu

Re: How to draw a standard normal denstity curve

lueryy2000 — Thu, 21 Apr 2011 15:01:08 GMT

Thanks. But I only want to have the standard normal pdf alone. Do you know if there is better way to do it. Below is my original code:

data try;
do z = -5 to 5 by 0.001;
if z gt 0 then pdf = 1- probnorm(z);
else pdf = probnorm(z);
output;
end;
run;

proc gplot data=try;
plot pdf*z ;
run;

Many thanks,
Lu

Re: How to draw a standard normal denstity curve

RickM — Thu, 21 Apr 2011 15:06:34 GMT

The probnorm function returns the CDF, try using pdf('normal',z).

Good luck!

Re: How to draw a standard normal denstity curve

lueryy2000 — Thu, 21 Apr 2011 15:22:15 GMT

I am sorry I don't get it. Is there a function that return the pdf? Thanks.

Re: How to draw a standard normal denstity curve

lueryy2000 — Thu, 21 Apr 2011 15:25:16 GMT

Sorry I just figured it out. It gives the perfect curves as I thought to be.
Thanks you very much!
Lu