Heads or Tails?
Heads? Or tails? We’ve all flipped a coin to settle a dispute, but is there really an equal chance that it will be heads or tails? Let's find out!
In cooperation with Money museum.
Did you ever flip a coin to resolve a disagreement or make a decision? Sometimes we entrust a coin with important decisions. We leave the decision to chance, believing the coin has an equal probability of landing heads up or tails up.
But why are we so sure the coin is fair?
What if we flip a coin 10, 100 or even 1000 times in a row? Will we really get the equal number of heads and tails? Or, in math terms, are heads and tails equiprobable*?
Scholars have been trying to answer that question for many years. In the early 20th century, a prominent British mathematician, Karl Pearson, took the trouble to toss a coin 12,000 times!
He got heads 6019 times.
Mr. Pearson ran the experiment again and tossed a coin… 24,000 times! (Can you figure out how long that took him?) And he got 12012 heads.
Both experiments showed that the coin had a slightly more than 50 percent chance of landing with heads up.
Is this so for every coin?
Let’s test Mr. Pearson’s findings. Together, we can toss coins more times than Mr. Pearson could.
So let’s start tossing coins!
*equiprobable is when two or more things have equal probability of happening.
- Project Facilitators