"I found that the averages were wrong because the Summary field was including the students who had no score entered, which brought the average down."
Better check that again. A summary field set to compute the average of a field will not include records where the summarized field is empty.
Will compute an average of 2, not 1.333...
Summary fields DO compute sub-totals, but only when it's placed inside a sub summary and sorted by the sub summary's break field. If you use a summary field inside a calculation, it computes a grand total instead of returning the sub total. There's function, however, that you can use to get sub totals from a summary field.
GetSummary ( SummaryField ; BreakField ) will return a sub total if the current found set is sorted by BreakField. Thus, you can use this function in a calculation to compute a value based on one or more sub totals.
For some reaon I convinced myself that a summary field set to compute the average of the field didn't work for me, but it checking it now it does. Thanks.
I'm having a similar (sort-of) problem. I thought using a report would be great, but I need to report the difference of each question field from pre-test to post-test. Unfortunately, it seems that reports are restriced to very certain calculations (i.e. I cannot take the difference). Is there any way to bypass this, or should I just use calculations?
You'll need to explain what you are trying to do and how you've structured your database before someone can offer some help. You can certainly take the difference between values in two or more records, but the details depend on what you've set up and what you want to do.