September 5, 201411 yr Greets, all: Â I'm creating a report where I need to average each heading's average but I'm scratching my head raw trying to get it to work. (Please refer to the attached.) Â For example, under Content Specialist, I want to average 2.13 and 2.71 which should equal 2.42 (4.84 / 2 = 2.42) but FileMaker has other plans and spat out 3.03...which is a result of taking all the gazillion records in the found set and averaging them out instead of averaging just the two (sub-summarized) numbers. Â I "get" that I need to create a new sub-summary but how should I code the (new) summary field so I get the average of the items listed under each heading? Â TIA for your help! Rich
September 6, 201411 yr For example, under Content Specialist, I want to average 2.13 and 2.71 which should equal 2.42 (4.84 / 2 = 2.42) Are we looking at the same picture? I see 3.13 and 2.71. Anyway, why would you want to average the averages? It skews the data.
September 6, 201411 yr Author Yup, it's 3.13. I didn't have my reading/computer glasses handy when I wrote that. Sorry! Y'know, I asked the very same question but that's what my boss wants so that's what she gets. :|
September 6, 201411 yr Well, she's not my boss, so that's not good enough for me. Perhaps you should show her the following example: A school has two classes. There are 9 students in the first class and all of them have a perfect score of 100. The other class is a remedial class; it has only one student with a score of 0. According to your boss, the overall school average should be calculated as follows: • Class 1 average = 9 * 100 / 9 = 100; • Class 2 average = 1 * 0 / 1 = 0; School average = ( 100 + 0 ) / 2 = 50 which is of course a complete nonsense, because in fact the overall school average is = ( 9 * 100 + 1 * 0 ) / ( 9 + 1 ) = 90 i.e. "a result of taking all the gazillion records in the found set and averaging them out instead of averaging just the two (sub-summarized) numbers". Now I'll make you a deal: show me a case where the average of averages has a meaning and I'll show you how to calculate it.
September 7, 201411 yr Author GREAT example! Thanks! I'm supposed to meet with her again about this Monday or possibly Tuesday, so stay tuned.
September 10, 201411 yr Author Sorry I didn't get back to y'all yesterday. I presented your outstanding example, Comment, and she "got it", so no averaging of averages. : )
September 10, 201411 yr Well, the example is rather trivial - but it's encouraging to hear that common sense prevailed, even in the education sector. Just for the record: there are special cases where the average of averages does have a meaning.
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