General Formula for Confidence Intervals (2 of 2)

---

Next section: Differences between means of independent groups, σ known

The general formula applies to a whole host of other statistics such as the difference between means and Pearson's correlation. The one exception to this rule you will encounter is that when confidence intervals on proportions (or differences between proportions) are computed, z rather than t is used even though the standard error is estimated.

Next section: Differences between means of independent groups, σ known