From Dwayne Wright PMP, PMI-ACP, CSM
Certified FileMaker Developer
Here is a closer look at the available options for summary fields.
TOTAL OF - Returns the total of a selected numeric field (or calculation field with a numeric result) for all the records in the current found set or sub-summary grouping. This would be used to give you a total of sales in a sales report. There is a check box option called "Running Totals" that will summarize the current total as to move from one record to the next . This is the equivalent of a spreadsheet sum function where 2 + 2 + 2 = 6.
AVERAGE OF - Returns the average amount of a numeric field (or calculation field with a numeric result) for the current found set. This can be used to give you the average sale in a sales report. Say you are doing a report on product sales for the month of July. You have a multiple structured pricing scheme based upon the quantity purchased on one invoice. The average summary field would be great in figuring out what your average profit is per unit by subtracting... well ... should I say it.... the average cost of the product for the month. There is a check box option that is labeled "Weighted Average." This will weigh the calculated result based upon a field that you choose in the scrollable list to the right. Average is the equivalent of (2 + 3 + 4) / 3 = 3
COUNT OF - Counts the number of valid, populated entries in an indicated field. It is important to know that the Count function is intelligent enough to ignore empty fields and will not count them. One popular method of using the Count option is in the sub summary part of a monthly sales report. Here you can get a count of the number of invoices for each month in the found set and using the Total option, you can get the total sales amount. For example for June 1999 (54 sales - $5,000) and for May 1999 (49 sales - $4800).
MINIMUM OF - The smallest value (number, date or time) of a particular field in the found set of records or for the set of records in a sub summary part. Using the same monthly sales report example discussed above where June 1999 (54 sales - $5,000 Smallest Sale Was $10.00) and for May 1999 (49 sales - $4800 Smallest Sale Was $20.00).
MAXIMUM OF - The largest value (number, date or time) of a particular field in the found set of records or for the set of records in a sub summary part. Using the same monthly sales report example discussed above... June 1999 (54 sales - $5,000 Largest Sale Was $500) and for May 1999 (49 sales - $4800 Largest Sale Was $300).
STANDARD DEVIATION FUNCTION - A statistical element that shows how much a field value deviates from one record to another. It has a checkbox labeled "By population" that changes it from a statistic to a population element. A good example of how Standard Deviation might be used is if comparing test scores for different schools, the standard deviation will tell you how diverse the test scores are for each school.
FRACTION OF TOTAL OF - Returns a fractional representation of a value you specify against all the values in a numerical field (or calculation field with a numeric result) for a found set of records.
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