LEARN · EXPLAIN · REVISE

A model has p=1/4. In 20k independent trials, find the expected number of occurrences.

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 / Foundation#Your turn

k=7

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

Expected count equals trial number times model probability.

Worked solution

Distinguish observed relative frequency from a model probability and describe the experiment.
Calculate or simplify this relation.
$E(N)=np=140/4=35$
The actual integer count need not equal its expectation.

The requested value is 35.

Checks and common pitfalls: The actual integer count need not equal its expectation.

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

Teacher preparation and assessment