8.3.1 - Confidence Intervals

The formula for constructing a confidence interval for the difference in paired means is almost identical to the formula for constructing a confidence interval for one mean. Note that the only change is the subscript d which stands for difference.

Confidence Interval for the Difference Between Two Paired Means
$$\overline{x}_d \pm t^* \left(\frac{s_d}{\sqrt{n}}\right)$$
$$t^*$$ is the multiplier with $$df = n-1$$