Here’s an easy exercise to show why understanding probability and statistics is important.
The Birthday Paradox
Ask your students to consider a group you know: Have them think about a group. This could be a group or friends on Facebook, Instagram, or the followers of a team or person at work.
How many shared birthdays do you think there are? Ask them to estimate how many people would need to be in the group to make it more likely (i.e. more than fifty-fifty chances), that two members share the same birthday.
The answer is to tell them that there’s a 50% chance that two members of the group share the same birthday. This will be hard for them to believe.
Most, if not all, of your students will instinctively think that you need a greater number than 23 people for this birthday match.
This paradox, also known as the birthday problem or the birthday paradox, is a fascinating starting point for psychology instructors to create a valuable student learning experience.
Coincidences Happen Often
This activity could be used in a statistics class or used to introduce probability theory. This activity could be used to help students think mathematically about probability, randomness, and chance. You might also encourage students to listen this hilarious BBC podcast that discusses the idea of randomness. Listen to the hosts (and mathematician Alex Bellos), discuss the birthday paradox at 15:31
“Most coincidences, when you actually crunch numbers, become a lot more amazing” – Alex Bellos, mathematician
Students could also be encouraged to test the birthday paradox as a group project or individual. They would need to find a way to access the birth dates for a group of 30 people to see if any match.
I was a huge fan of the series and checked out the cast list for The Walking Dead to find that Steven Yeun (Glenn), and Tom Payne(Jesus) both celebrated their birthdays on the 21st December.
What are the odds of this happening? It’s much more likely than we think.