Simulating a coin toss in excel

I guess when you start to look at gambling theories or probabilities the natural place to start is the coin toss.

This relates especially well to roulette as a Heads or Tails coin toss kinda relates to Red or Black (not quite because of those pesky zeroes and double zeroes (and some other mechanical factors)).

Although Excel won't produce necessarily a true random number (it's a pretty poor random number generator (will discuss in another article), for our sake it will do.

Generating a random number between two values

The first thing we need to do is get excel to generate a random number between 2 values.   One number to represent heads and another to represent tails.   In this case 0 and 1.   0 will represent Heads and 1 will represent tails.

To do this

1) Open Excel
2) Open a new Workbook
3) Click on any cell and in the formula bar type in the following function

=RANDBETWEEN(0,1)

And here is how this looks on my machine (I'm using excel on a Mac)

As you can guess from the formula, it randomly produces a number between 0 and 1 which funnily enough would be the values 0 and 1.   

Making it say Heads or Tails

As you can guess from the formula, it randomly produces a number between 0 and 1 which funnily enough would be the values 0 and 1.   

It would be cooler if it said Heads or Tails rather than 1 or 0.   And it's pretty easy to do in Excel.   We'll just use the IF formula.

So in your cell, just replace the previous formula with this.

=IF(RANDBETWEEN(0,1) = 0,"Heads","Tails")

And this will now check the randomly generated number, and if it's 0, it will display Heads in the cell, and if it's 1, it will display 1.

And here is how this looks on my machine

Generating lots of numbers

So we've generated one simulated coin toss but we obviously want to generate lots of numbers.  So to do that all we need to do is grab our cell by the bottom right hand corner and drag down.

And now you can see below, i've generate 20 coin tosses using the above method.

Pretty easy to do right.   And we can use this in the future do lots of things.   Pick cards randomly, perform probability calculations etc.  Test for yourself if magic betting systems such as martingale is a good idea (btw it's not).

Google Docs

And the exact same thing works in Google Docs.

Hope you found this useful