7th Grade · Statistics & Probability
Probability Model
7.SP.C.7
Definition
A mathematical description that assigns a probability to each outcome in a sample space. Requirements: each probability is between 0 and 1, and all probabilities sum to 1.
Examples
- A model assigning 0.50, 0.25, 0.125, 0.125 to four outcomes sums to exactly 1.
- A probability model must account for every possible outcome.
Key rule
All probabilities must be ≥ 0 and must sum to exactly 1.
Memory hook
Every outcome gets a probability, and they all add to 1.