This simple example follows a pattern, but the algorithms behind computer number generation are much more complicated (based on distributions like the Bernoulli distribution or Poisson distribution), mimicking randomness much better than I can do here. Let’s take the starting number 77:įollowing the same algorithm, the second “random” number would be: For example, “take a number x, add 900 +x, then subtract 52.” In order for the process to start, you have to specify a starting number, x (the seed). You can mimic randomness by specifying a set of rules. Why are Seeds Needed?Ĭomputers don’t generate truly random numbers-they are deterministic, which means that they operate by a set of rules. But if you revert back to a seed of 77, then you’ll get the same set of random numbers you started with.
If you type “99”, you’ll get an entirely different set of numbers. If you typed “77” into the box, and typed “77” the next time you run the random number generator, Excel will display that same set of random numbers. If you enter a number into the Random Seed box during the process, you’ll be able to use the same set of random numbers again. Having such a large range for seeds (0 to 1+ billion) pretty much ensures that you don’t get the same random seed isn’t used twice - unless you want to.įor example, let’s say you wanted to generate a random number in Excel (Note: Excel sets a limit of 9999 for the seed). At time I am writing this sentence it is 11:01:46 EST on February 5, 2017: 1486310506 seconds after 1-1-1970 (you can find the current Unix time here). This can be any number, but it usually comes from seconds on a computer system’s clock (Henkemans & Lee, 2001).Ī computer counts seconds from Janua system called Unix time. A random seed is a starting point in generating random numbers.A random seed specifies the start point when a computer generates a random number sequence.
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