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McGinty McGinty is offline
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Default Help picking a random number from a given distribution

Thanks, that's helpful. I'm using Excel 2003 so I'll try and keep it simple
and stay within their native functions. I'm still trying to incorporate
range however.

What I'm doing is building a model that will allow the user to input the
minimum and maximum possible values (between 0 and 1) and then have Excel
pull a random number from a normal or other distribution. Your suggestion of
=NORMSINV(RAND()) got me halfway there but I'm trying to figure out a way to
incorporate the range the user inputs. It could also be that I need to
assume some mean and standard deviation. =NORMSINV(RAND()) uses 0 and 1
respectively.

Any ideas or places to look?

Thanks

McGinty


"Jerry W. Lewis" wrote:

Theoretically, =NORMSINV(RAND()) would be a normal random number. In
practice, prior to Excel 2003 NORMSINV() was too inaccurate for for this to
be acceptable even for non-stringent applications. Alternately you could use
Ian Smith's inv_normal() function instead of the native Excel function
NORMSINV()
http://members.aol.com/iandjmsmith/Examples.xls

Another approach would be to use the Box-Muller method
=SQRT(-2*LN(RAND()))*COS(2*PI()*RAND())
or
=SQRT(-2*LN(RAND()))*SIN(2*PI()*RAND())

Jerry

"McGinty" wrote:

Is there a way for me to have Excel select a random number from a given,
e.g., normal distribution? Also can I put a range on the distribution?

Thanks in advance