why is there a "Random Number" key on my calculator?

I use my pocket calculator for simple math and trig functions .
I think I once learned that random numbers are useful in complicated forms of math( that I know nothing about-- maybe modelling atomic behavior, or statistics, or computer games?)
But a pocket calculator with a 10 digit display ain’t no complex computer using a large data base to work from.

So why do you need the “random” key ? And why is the random number always less than one?

I know that one way of generating random numbers takes square roots and extracts the middle digits --but those middle digits don’t have to be less than
one.

(

That part, at least, I can answer. When you’re picking random numbers, you have to pick them from some distribution: Practically speaking, this means you need to have a maximum and a minimum number that can be picked. If you were writing a random-number generator, you could equally well choose any maximum or minimum. It’s convenient, though, to choose your numbers between 0 and 1, because it makes it easy to convert to other ranges. If, for instance, you want a number between 0 and 10, then you just take your original number and multiply by 10.

I can think of a number of uses for a random number function on a calculator, but they would all really only be worthwhile for a programmable calculator, which I gather yours isn’t. In which case, I’d guess that it’s just something that the calculator designers realized they could add, and decided to do so, even if it doesn’t have much use.

The random number generators on calculators I am familiar with give a random number between 0 and 1 with a uniform distribution. Given that it is easy to get a uniform distribution between any two numbers by multiplying and adding constants.

We used the random numbers to fill out the stupid drug surveys they gave you in middle school and high school because we did not want to give information that would be used against us. That is probably not what HP had in mind.

Read the stuff in the link below for some ideas on the uses of a random number generator. As Chronos mentioned a lot of it may be out of the useful abilities of a non-programmable calculator but at least you can see some uses for it.

http://random.mat.sbg.ac.at/~ste/dipl/node9.html

Even then, I don’t see why you’d want a random number key. Random number function, yes, but a whole key (or even part of one)?

What model is this calculator? Is it a scientific calculator?

Random numbers are most often, these days, used in games. To determine where the next asteroid will appear on your phone’s solitare game.
They can also be entertaining when inserted into a graph equation.

The reason you have it on your calculator is that it was probably the first Basic function, back when it was a Dartmouth program and Bill Gates was still a student.

I’ve always used those for fun and along the lines of a randomized portable ‘spinner’ that I can use to make unimportant decisions…

For instance… if it’s less than .4, I’ll go and stop off at the library after work, otherwise I’ll go straight home. :slight_smile:

I just checked the calculator I have at my desk… (two calculators, actually, but they both have the same layout. Probably ‘casio semi-scientific’ or something like that.)

Neither of them have rand as a dedicated key - it’s inverse decimal. (First the [inv] key, and then the [.] key used to mark the decimal point in 4.58 )

FWIW

I use it instead of dice, or instead of a spinner in games that have one. That way it eliminates the advantage of people who’ve learned to throw the dice or spin the spinner just right.