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### Course: AP®︎/College Statistics>Unit 10

Lesson 8: Confidence intervals for the difference of two proportions

# Two-sample z interval for the difference of proportions

You might need: Calculator,Z table

## Problem

Marta created an app, and she suspected that teens were more likely to use it than adults. She obtained separate random samples of teens and adults. Here are the results:
Yes$54$$26$
No$66$$104$
Total$120$$130$
She wants to use these results to construct a $95\mathrm{%}$ confidence interval to estimate the difference between the proportions of teens and adults that use her app $\left({p}_{\text{T}}-{p}_{\text{A}}\right)$. Assume that all of the conditions for inference have been met.
Which of the following is a correct $95\mathrm{%}$ confidence interval based on her data?