LEARN · EXPLAIN · REVISE

A representative sample estimates a proportion 1/4 in a population of 80k. Estimate the corresponding count.

Read the idea, work independently, then explain what changed.

TOPIC 01

Statistics: mixed assessment

A mixed assessment: identify the method, justify it and revise your reasoning.

Use one hint at a time. A correction explains what changed, not just the final answer.

01 / Foundation#Your turn

k=7

Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1

Translate counts into sample proportions and keep classes, units and uncertainty visible.

Hint 2

Multiply the estimated fraction by the population size.

Worked solution

Translate counts into sample proportions and keep classes, units and uncertainty visible.
Calculate or simplify this relation.
$\hat N=560/4=140$
The estimated count inherits sampling and coverage uncertainty.

The requested value is 140.

Checks and common pitfalls: The estimated count inherits sampling and coverage uncertainty.

Think first. Reveal a hint when the class is ready.

Teacher preparation and assessment