Confidence intervals for proportions are commonly quoted in news reports for polls, typically as the “margin of error, 19 times out of 20.” In this video we’ll see how a confidence interval for a proportion is constructed, to give a range of plausible values for the proportion in the population or the theoretical world based on the estimated proportion we’ve observed in the real world.
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Notes on the video: Confidence Intervals for Proportion
A point to consider for this video:
Substituting 1/2 for p in the margin of error of a confidence interval is one way to deal with the fact that we don’t know the theoretical world proportion. Why might substituting in the estimated value of p be preferred?