A Sample Speaks for Its Own Population

You'll learnto size a claim to its sample: population reach, margin of error, and cause.

A sample estimates its own population, a margin of error brackets that estimate, and an observed association is not a cause; points leak in generalizing beyond the population sampled, misreading the margin, and claiming causation from an observational link.

8 STEPS · 6 QUICK CHECKS · the margin brackets the estimate · association ≠ cause · v2

sample → population

Before you start

What you're looking at

A number line showing a poll estimate of 58% with a margin bracket from 54% to 62%, beside two cards.

The question

How far does a sample's result reach, and what does its margin of error actually mean?

Watch for

Watch the estimate become a bracket in both directions; inside is consistent, outside is not.

What the symbols mean

The band is the margin bracket 54% to 62%, the mark is the 58% estimate; cards list three checks.

Step 1 / 8