7.3 A population proportion -- rrc math 1020  (Page 4/24)

References

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Chapter review

Some statistical measures, like many survey questions, measure qualitative rather than quantitative data. In this case, the population parameter being estimated is a proportion. It is possible to create a confidence interval for the true population proportion following procedures similar to those used in creating confidence intervals for population means. The formulas are slightly different, but they follow the same reasoning.

Let p′ represent the sample proportion, x/n , where x represents the number of successes and n represents the sample size. Let q′ = 1 – p′ . Then the confidence interval for a population proportion is given by the following formula:

(lower bound, upper bound) $=(p^{\prime }–EBP,p^{\prime } +EBP)= \left(p^{\prime }–z\sqrt{\frac{p^{\prime }{q}^{\prime }}{n}},p^{\prime }+z\sqrt{\frac{p^{\prime }{q}^{\prime }}{n}}\right)$