# Understanding probability & the relationship with inference

## Learning outcomes

On watching this video, students should be able to:

1. Explain the frequentist definition of probability
2. Explain how probability is used in statistical inference
3. Explain the concept of independence and appreciate why it is an important concept in statistical inference.
4. Identify and calculate marginal, joint and conditional probabilities in a contingency table.
5. Understand that when two events are not independent, we cannot calculate their probability by simply multiplying each of their marginal probabilities.
6. Understand how easy it is to flip the interpretation of a conditional probability and draw wrong conclusions.
7. Use contingency tables and probability trees to help understand probabilities.

Correction

05:10: The slide says “P(G,G,B)”, this is not quite the correct notation because this would normally be read as the probability of having 2 girls and a boy, but the point about multiplying independent events to work out the probability of a sequence is true.