Inference from sample statistics

About this lesson

Inference from samples on the SAT: random samples and the population they describe, estimating a population count from a sample proportion, margin of error and the range of plausible values, the effect of sample size, and spotting biased sampling methods.

On the Digital SAT, inference from sample statistics is a Problem-Solving and Data Analysis skill. A question usually describes a survey or a random inspection and then asks for an estimated count in the population, the plausible range given a margin of error, which sampling method is reliable, or which conclusion the data support.

There is almost no calculation, so points are lost by reading too much into the data: stretching one school's result to a whole city, treating a margin of error as a certainty or as a range for individuals, or trusting a large sample even when it is biased. This lesson focuses on the key question of where the sample came from, how to turn a margin of error into a range, and the cautious wording that correct answers tend to use. It ends with 6 self-graded practice questions, each with a full explanation.