LEARN · EXPLAIN · REVISE

Two batches have 2k successes in 5k trials and 3k in 10k. Find pooled relative frequency.

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

TOPIC 01

Probability: 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 / Standard#Your turn

k=9

Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1

Distinguish observed relative frequency from a model probability and describe the experiment.

Hint 2

Pool counts and trial totals before dividing.

Worked solution

Distinguish observed relative frequency from a model probability and describe the experiment.
Calculate or simplify this relation.
$f=(18+27)/(45+90)=1/3$
A simple average of batch percentages ignores their unequal sizes.

The requested value is 0.33333333.

Checks and common pitfalls: A simple average of batch percentages ignores their unequal sizes.

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

Teacher preparation and assessment