Probability.
Count complete outcomes, interpret conditional information and evaluate probability models and simulations.
Work through the topic
Learn the method, follow the examples, then try the worksheet.
- 01
Compound events
Describe combined events with complete sample spaces, and distinguish “and” from inclusive “or”.
- 02
Systematic counting and the multiplication principle
Count multi-stage possibilities using the multiplication principle, while respecting restrictions.
- 03
Factorials and simple arrangements
Use factorials for ordered arrangements and identify when order creates overcounting.
- 04
Conditional language and restricted sample spaces
Restrict the sample space to the given information before finding a conditional probability.
- 05
Conditional probabilities from tables/trees
Read conditional probabilities from tables and probability trees, using the total of the relevant group.
- 06
Replacement and dependence
Update probabilities when an item is not replaced, and test independence mathematically.
- 07
Conditional versus unconditional probabilities
Compare a probability for the whole group with one calculated after information is supplied.
- 08
Designing and interpreting simulations
Design fair probability simulations and interpret their variation without treating estimates as exact laws.
Topic review
Revisit the key ideas, then choose a practice paper.