Statistical Sampling
SAT Math — Data Analysis, Statistics & Probability
Master how to draw valid conclusions from data — a key SAT skill!
1. Population vs. Sample
Population
The entire group being studied.
Example: All 9th graders in a country.
Often too large to study completelySample
A subset of the population selected for study.
Example: 200 randomly selected 9th graders.
Used to make inferences about the population
Key Idea: It is often impossible or impractical to study the entire population, so we use samples. The goal is for the sample to accurately represent the population.
2. Why Sampling Matters
✅ Good Sample
- Allows valid conclusions about the entire population
- Is randomly selected
- Is large enough to reduce variability
❌ Bad Sample
- Leads to incorrect conclusions
- Over-represents or under-represents certain groups
- Cannot be trusted to reflect the population