Key Terms
Addition Principle
When choosing between two groups with no overlap, add.
Principle)
When making a sequence of choices, one after another, multiply.
Example
8 phones, 3 defective, 5 good. Select 2.
Formula
N! / (r1!
Logic
For each object, there are 2 choices — include it or leave it out. Multiply 2 by itself n times.
Step-by-step
1. Identify n from the exponent.
Experiment
Any activity with an observable result (rolling a die, drawing a card) Outcome: one possible result Sample space (S): th