cmell is perfectly correct in stating that random numbers are chosen (read:
generated) for a reason. In
computer programming, random numbers are extremely useful. In most
hard sciences, all
simulation programs will use some form of random numbers to help
model uncertainty.
It is important to note that random numbers need not have a flat distribution (also called a uniform distribution). They can be generated according to any conceivable probability distribution function, according to the needs of the researcher/programmer. Some common distributions from which random numbers are generated are normal, normal with skew, Fisher's F, Student's t, and the famous chi squared.