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MathGroup Archive 1995

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Lottery

  • To: mathgroup at christensen.cybernetics.net
  • Subject: [mg409] Lottery
  • From: donald darling <ddarling at math.uci.edu>
  • Date: Sun, 15 Jan 95 12:55:44 -0800

   Yet another simple procedure to select, without replacement, a random 
sample S of size k from the first n integers.

(S={};CS=Range[n];For[j=1,j<=k,j++,
	     AppendTo[S,x={CS[[ Random[Integer,{1,n-j+1}] ]]}];
	     CS=Complement[CS,x] ];Flatten[S])

   Note that if k>n/2 it is quicker to select a sample of size n-k and then 
choose CS, the complement of S, from the above.
	   
	   



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