Probability and Evidence

Probability and Evidence

An understanding of probability is important in medicine, law and wider society. These problems invite you to consider some scenarios where interpreting probabilities incorrectly can have serious consequences.

Introductory Video 

Age 11 to 16
An introductory video to the Probability and Evidence collection

Spots and Measles 

Age 11 to 16
Challenge Level
99% of people who have measles have spots. Ben has spots. Do you think he has measles?

Do Rare Events Happen? 

Age 11 to 16
Challenge Level
I'd be very surprised if I had three children all with the same birthday, but I read in the paper that it happened to one family...

The ELISA Test 

Age 14 to 18
Challenge Level
In 1% of cases, an HIV test gives a positive result for someone who is HIV negative. How likely is it that someone who tests positive has HIV?

Matching Criminals 

Age 14 to 18
Challenge Level
DNA profiling is an invaluable tool for the police. However, when it comes to probability, things aren't always as straightforward as they seem.