7. A Confidence Interval for Population Mean Difference of Matched-Pairs Data

Following the same logic of a level C = (1 – α) ⋅ 100% confidence interval, we use the standard formula:

point estimate ± margin of error

Before we jump to the confidence interval formula, we need to see a bit of notation. The population mean difference in the two data sets is denoted by μd, and we represent the sample mean difference in the two data sets by . The standard deviation of the difference in the two data sets is represented by sd.

Our point estimate of μd is, thus, . The formula for a level C = (1 – α) ⋅ 100% confidence interval is

section11-11

which, in interval notation, is:

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