7th Grade · Statistics & Probability
Random Sample
7.SP.A.1
Definition
A sample in which each member of the population has an equal probability of being selected. Reduces bias. Methods include random number generators, lottery draws, and systematic sampling.
Examples
- Assign each of 500 students a number, then draw 50 at random.
- Non-random methods like asking only friends (convenience sample) are biased.
Key rule
Random sampling reduces bias and makes the sample more representative.
Memory hook
Every member has the same chance of being picked.