AP Statistics / Unit 3: Inference for Categorical Data: Proportions
3.7 Carrying Out a Test for a Population Proportion
Notes
$$z=\frac{\hat p-p_0}{\sqrt{\frac{p_0(1-p_0)}{n}}}$$
- Use $p_0$ (not $\hat p$) in the standard deviation and in the large counts check.
- Conclude in context with the p-value and $\alpha$.
Practice
$\hat p=0.55$, $p_0=0.5$, $n=100$. $z=$
$\displaystyle \frac{0.05}{0.05}$.
In a one-proportion z test, the standard deviation uses:
We assume $H_0$ is true.
The conclusion of a test should include:
Link the decision to the question.
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