Horst Kraemer wrote: > On Mon, 11 Aug 2003 17:10:38 -0500, "K L" <[EMAIL PROTECTED]> wrote: > >> Folks, >> >> I have one question. Please let me know if any of you know the >> answer to my question. >> >> I have a normal distribution with mean = 50 and standard deviation = >> 5 >> I want to divide this distribution into two separate normal >> distributions each with mean = 25 so that when I add them I will get >> my original distribution. > >> Do any one know how to find the two separate distributions? > >> Is the answer distribution 1 : N(25,3) and distribution 2: N(25,4) >> correct ? > > If X is N(25,3) and Y is N(25,3) and X and Y are *uncorreleted* RVs, > then Z=X+Y is N(50,5). If you mean by "add two distributions" that you > are going to add the RVs defined by these distributions then your > answer is correct - if you add the condition that X and Y are > uncorrelated.
Also, I believe the usual notation uses N(a,b), where a=mean, b=variance (and specicically not b=standard deviation): thus you really need N(25,9) and N(25,16) to "add" to get N(50,25). David Jones . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
