Confidence interval for difference

A 95% confidence interval for the difference between two group means can be found from the standard error of the difference between the sample means.

Confidence intervals are now evaluated and interpreted in a few examples.

Properties

Confidence intervals for the difference between two group means have the same properties as the confidence intervals that we investigated in earlier sections. They vary from sample to sample and:

The confidence interval will include the true difference, µ2 − µ1, in approximately 95% of such repeat samples.


Demonstration of properties