Question

Look in the newspapers, magazines, and other news sources for results of a survey or poll that show the confidence interval, usually shows as a +/- some amount.  Describe the survey or poll and then describe the interval shown.  How does knowing the interval, rather than just the main result, impact your view of the results?

Answer 1

Let's look at the following part of the article:

The 95% confidence interval of the proportion of middle school students who were current e-ciggarette use is given which is:

(95% CI, 9.4% - 11.8%)

The above interval tells us that if multiple samples are drawn from the same population, proportion of the 95% of the samples will fall in the above interval. Knowing the above interval, we are 95% certain that the true population proportion will fall between 9.4% and 11.8%. If we had looked at the main result instead, it would have showed us the proportion of the particular sample but we also know that the true population proportion would change depending on the sample used. Hence, knowing the confidence interval gives us a better picture of the results.