Updated: 2/23/2009. This calculator allows users to produce the margins of error when combining counts or proportions for a number of geographic areas.  It also allows users to test significant differences between two estimates.

This spreadsheet allows you to input two values with either the margins of error or the confidence intervals (depending on which two you have available to you). The calculations are then performed based on the formula provided at the annual meeting in the Powerpoint presentation. It provides a "yes" or "no" answer to whether there is a statistically significant difference between the two estimates.