UTO Help: Reporting Options -- Calculate

USA Trade®
Online

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USA Trade Online's calculation option allows you to do further analysis with the available data. For example, you can use central tendency measurements (average, median), as well as measures of variation (standard deviation, variance) to better determine the distribution and pace of both imports and exports. If you are already familiar with a statistical software program, you can also download your report in an ASCII format and import it into your statistical program or download the information directly into Microsoft Excel (see the section on downloading for more information).

Using USA Trade Online's Calculation Option

To access the calculation options, you must first select "Calculate" from the Options list (see Figure A for a list of the options that will appear). Next, you must choose from the different dimensions offered. That is, do you want to look at calculations by Commodity, Country, District, and/or Time? The only dimension you can't select is Measures since it is the basis for the values in the chart. You have eight different statistical calculations to choose from:

Totals. Calculates the total of the selected column or row.
Percentages. Calculates the percent share that each data cell contributes to the selected row/column’s total.
Average. Calculates the average numerical value of the selected column/row. The average, also know as the mean, is the value obtained by dividing the sum of a set of quantities by the number of quantities in the set.
Median. Calculates the median numerical value of the selected column/row. The median is the value below which 50% of the values fall.
Minimum. Displays the minimum value for the selected column/row.
Maximum. Displays the maximum value for the selected column/row.
Variance. Calculates the variance of the selected column/row. The variance is a statistical measure of the variability of measured datum from the average value of the set of data. The higher the variance, the more the individual data values deviate from the average value. For example, the data set {5, 5, 5} will have a sample variance of 0 whereas the data set {10, 5, 0} will have a sample variance of 25.
Standard Deviation. Calculates the standard deviation of the selected column/row. The standard deviation is another measure of variability and is equal to the square root of the variance.

Finally, you have the option of displaying "Values and Percentages" together. This option is only available if you've enabled "Percentages" in the Calculations box. Figure B shows the percentage distribution of Asparagus imports by country. It is important to note that while "Total" equates to "World Total" conceptually when all countries are selected, the actual World Total country dimension has been deselected to avoid double-counting.

Once you've made your desired selections, click the OK button to reload your report with the calculations of interest. The report will load with an additional row for each selected calculation option except for Percentages, which are represented in an additional column (see "Average" and "Value %" in Figure B).

Figure A: USA Trade Online's Calculation Options
Calculate Option Screen

Figure B: Asparagus Imports, Percentage Distribution by Country

Helpful Hints and Related Information

It is best to use this feature on the Report Table page (as compared to the "View Chart" option). Sticking to the table format enables you to see the calculations you are making.
When calculating data statistics, be sure to not include a folder and its subfolder in the same column. This will result in the double-counting of data and skew the calculations. This most often happens when calculating country percentage shares. If one has "World Total" selected along with all the individual countries, the shares would show 50 percent for World Total and the other 50 percent would be distributed amongst the individual countries, resulting in shares that are exactly half of the desired value. To correct this problem, first change the countries selected through your Country dimension to exclude "World Total" and then continue with the Calculate option as described above.