How to generate random numbers with specific mean

Question

Is there any formula that I can understand which will allow me to generate random numbers with a specific mean. I'm using java. Thanks

Answer 1

They will all be random except for the last...

Here's an algorithm:

Mean = total/count

mean * count = total

So you know in advance what the total of the N statistics must be.....

So then you calculate S, the running total of N-1 random statistics

The Nth statistic must be total - S...

here some working code..........

public static void main( String args[])

{

int mean,N;

mean=N=0;

if (args.length>1)

{

mean = Integer.parseInt(args[0]);

N = Integer.parseInt(args[1]);

}

else

{

System.out.println(" Please input the mean and the count on the command line ");

return;

}

int randNum=0;

long total = mean*N;

long running_total = 0;

int [] randStats = new int[N];

for (int iLoop=0; iLoop<N-1; iLoop++)

{

randNum = (int) (Math.random()*999 +1);

System.out.println(" random # " + randNum);

randStats[iLoop]=randNum;

running_total += randNum;

}

System.out.println(" Running total is " + running_total);

randStats[N-1] = (int) (total - running_total);

System.out.println(" random # " + randStats[N-1]);

long sum=0;

for (int iLoop=0; iLoop<N; iLoop++)

{

sum+=randStats[iLoop];

}

System.out.println(" mean verified : "+ sum/N);

}

}