It's Not Fair!

I have two children, both of whom at this point in their lives are fairly competitive.  Even when it comes to getting their teeth brushed, each wants their teeth brushed first!  So, my husband flips a coin to decide.  It's a fair way, right?

Well, after several days of losing the coin toss, SpiderGirl had a meltdown.  "It's not fair!" she declared.  "I ALWAYS lose!"

Well, SpiderGirl may have been right that she had been losing a lot... BUT, was the coin toss fair?  We decided to find out (in the middle of a day, when everyone was rested and happy).

This experiment was conducted on a quarter.  SpiderGirl recorded, counted, and added the final total.  BatBoy announced the results at the end of each toss (until he got tired of it and left).  I flipped the coins and set up the chart.

After 10 trials of tossing the coin, but letting it fall to the table on its own, we suspected that it was perhaps heavier on one side than the other.  However, by catching the coin after it had been tossed, the results were pretty even between heads and tails.  And the greater the number of tosses, the greater seemed the chances of half of the tosses ending in heads and half ending in tails.

This experiment was SpiderGirl's introduction to both frequency tables and probability.