Add Calculations to a Report Column

You can add rows to the bottom of a column to display calculations performed on the column’s data. You can also perform calculations on data rollups.

The Calculations window displays all the calculations that can be performed on the data in the column. If the report does not have rollup columns, the Rollup Calculations section does not appear. Also, columns that do not contain numeric values have only the Minimum, Maximum, and Median calculations available.

You can also add calculations from a selected column’s Design tab.

1. Right-click the column and select Edit Calculations.
   The Calculations window opens.
2. If you select a rollup column, select the options you want for the column.
   1. Select the Total check box to display the total value of the output column for all records.
   2. Select the Minimum or Maximum check boxes to display the minimum or maximum values of the output column for all records.
   3. Select the Weighted Average check box to display the weighted average of the column for all records.
   4. Select the Average check box to display the average value of the output column for all records.
   5. Select the Median check box to display the median (middle) value of the output column for all records.
   6. Select the Standard Deviation check box to display the standard deviation of the column for all records.
      Standard deviation is the square root of the variance. It projects how various values in a set of values deviate from the mean for that set.
3. Select calculations for columns.
   1. Select the Total check box to display the total value of the output column for all records.
   2. Select the Minimum or Maximum check boxes to display the minimum or maximum values of the output column for all records.
   3. Select the Weighted Average check box to display the weighted average of the column for all records.
   4. Select the Average check box to display the average value of the output column for all records.
   5. Select the Median check box to display the median (middle) value of the output column for all records.
   6. Select the Standard Deviation check box to display the standard deviation of the column for all records.
      Standard deviation is the square root of the variance. It projects how various values in a set of values deviate from the mean for that set.
   7. Click the Weighted Column drop-down list and select the column to use in conjunction with the current column to derive the weighted average.

      This drop-down list is activated when the Weighted Average report or rollup calculation is selected, and displays only numeric columns you can use with weighted averages.

      For example, if you have a report with column X showing the number of incidents solved by a group, and column Y showing the average amount of time spent solving the incidents, a weighted average calculation can determine the average amount of time spent solving each incident regardless of how many incidents each group solved.

      That is, if group A solves 30 incidents and averages 30 minutes per incident, and group B solves 10 incidents averaging 110 minutes per incident, a normal average would calculate 70 minutes per incident, which would not reflect the different number of incidents for each group. A weighted average would show a more accurate average of 50 minutes per incident, since it takes the number of incidents solved by each group into account.

      The calculation used to determine weighted averages is (x1*y1)+(x2*y2)) / (x1+x2) or, in this example, ((30*30) + (10*110)) / (30 + 10) = 50.

4. Click OK.