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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 you have two independent normal random set N(25,3) and N(25,4) and 
add them together piecevise, you will get N(50, 5). In general for two 
independent set the mean is the sum of the components and also the 
variances are the sum of the variances of the components.

If you reverse it and from a normal random set N(50,5) substract an 
independent N(25,3) normal random set piecevise, then you will get N(25, 
5.831) being the new std = sqrt(std1**2 + std2**2)

http://localhost/cgi-bin/igperl/igp.pl?dir=test&name=addeddistr


Now the insteresting point: If you have a normal random set N(50,5) and 
make two distributions on that manner, that divide each number on the 
ration of the expected new means ($a = $orig * $mean1 / $meanorig  and 
$b = $orig - $a) then the resulted standard deviation also will be 
divided by the ration of the expected new means, on that manner that the 
sum of the two standard deviations will be the original (if the given 
new mean is larger than the orginal, then that std will be larger also), 
so N(50,5) divided onto two equal half each element will result 
N(50,2.5), N(50,2.5) sets

http://localhost/cgi-bin/igperl/igp.pl?dir=test&name=dividedistr

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