The scripts below do normal distribution stuff, but they are not what you have asked for. However, I have needed what you want in the past, and rather than spend too long looking for a method I simply generated 2000 random values drawn from the normal distribution in Excel (using the Data Analysis add-in) and stored them as a custom property. Randomly selecting one of those values each time gives a very close approximation to randomly selecting from the normal distribution. If you need the values (or any number of them, really) then let me know.
--calculates an approximate Inverse Normal Integral --using the rational approximation from the --Handbook of Mathematical Functions, National Bureau of Standards, 1968 on mouseUp --get area of interest, Q ask "What Q?" put it into Q put sqrt(ln(Q^(-2))) into t put t*t into t2 put t2*t into t3 put t-(2.515517+0.802853*t+0.010328*t2)/(1+1.432788*t+0.189269*t2+0.001308*t3) into x put x end mouseUp --calculates an approximate Normal Integral (tail from z to inf) --using the rational approximation from the --Handbook of Mathematical Functions, National Bureau of Standards, 1968 --checked against table A3 in Snedecor & Cochran on mouseUp --get value of interest, Z ask "What Z?" put it into Z put 1/(1+0.2316419*z) into t put t*t into t2 put t2*t into t3 put t3*t into t4 put t4*t into t5 put 1/(sqrt(2*pi))*exp(-z*z/2) into fx put fx*(0.31938153*t-0.356563782*t2+1.781477937*t3-1.821255978*t4+1.330274429*t5) into area put area end mouseUp -- Michael J. Lew Senior Lecturer Department of Pharmacology The University of Melbourne Parkville 3010 Victoria Australia Phone +613 8344 8304 ** New email address: [EMAIL PROTECTED] ** Archives: http://www.mail-archive.com/[email protected]/ Info: http://www.xworlds.com/metacard/mailinglist.htm Please send bug reports to <[EMAIL PROTECTED]>, not this list.
