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Hypothesis testing
Lesson 5 of 10

Setting up hypotheses

Objective. State null and alternative hypotheses correctly for a test.

The key idea

H₀ states no change and always uses equality. H₁ states the suspected change and decides whether the test is one-tailed or two-tailed.

Worked example

A coin is suspected of favouring heads. Write the hypotheses.

H₀: p = 0.5, H₁: p > 0.5
Illustrated card showing H₀: p = 0.5, H₁: p > 0.5
  1. 1Let p be the probability of heads.
  2. 2H₀: p = 0.5 (fair).
  3. 3H₁: p > 0.5 (one-tailed, favours heads).

Answer: H₀: p = 0.5, H₁: p > 0.5

Practice

Each question comes with a picture and a listen button. Try it first, then reveal the answer.

Common mistake. Putting the claim being tested into H₀ instead of H₁.

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