AP Statistics / Unit 3: Inference for Categorical Data: Proportions
3.5 Setting Up a Test for a Population Proportion
Notes
- $H_0: p=p_0$ (no change). $H_a: p>p_0$, $p<p_0$, or $p\ne p_0$.
- Hypotheses are about the parameter, never $\hat p$.
- Choose a significance level $\alpha$ (often 0.05).
Practice
A company claims 80% satisfaction; you suspect less. $H_a$:
Your suspicion goes in $H_a$.
Which is a correct null hypothesis?
About the parameter, with equality.
A two-sided test uses:
Either direction.
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