Random number generators: Determine the usual distribution/density for the output of random number generators? When you use Excel and enter the command RAND() into a cell, you will get a random number between zero and one, but what is the density function? [RAND() is located in the Math & Trig part of the special formulas that Excel provides.] If you want a random number drawn from a special distribution, then you have to supply the conversion math. Sometimes, it's not easy.