AP Statistics / Unit 3: Inference for Categorical Data: Proportions
3.10 Constructing a Confidence Interval for the Difference Between Two Population Proportions
Notes
$$(\hat p_1-\hat p_2)\pm z^{*}\sqrt{\frac{\hat p_1(1-\hat p_1)}{n_1}+\frac{\hat p_2(1-\hat p_2)}{n_2}}$$
- Conditions: two independent random samples (or random assignment), 10% condition, large counts in each.
Practice
$\hat p_1=0.6$, $\hat p_2=0.5$. The interval's center:
$\hat p_1-\hat p_2$.
The large counts condition requires at least 10 successes and failures:
Both samples.
The CI is for:
Parameters.
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