Wikipedia:Reference desk/Archives/Mathematics/2013 December 23
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December 23 edit
Average edit
I'm desperately trying to figure out my average grade. The grade includes one major exam, three tests (which count as much as the exam, so each counts one third) and another one (which counts one fourth of the exam). Without the latter, it would be (3*exam+test1+test2+test3)/6. However, now I'm very confused. Hope you can help me. Thanks.--2.246.17.72 (talk) 21:16, 23 December 2013 (UTC)
- Sounds like (3*exam+test1+test2+test3+0.75*test4)/6.75 --David Biddulph (talk) 21:21, 23 December 2013 (UTC)
- I think it is ( 1*first_exam + 1/3 * (test1 + test2 + test3) + 1/4 * second_exam) / 2.25
- Where 2.25 is 1 + 1/3 * (1+1+1) + 1/4 202.177.218.59 (talk) 00:05, 24 December 2013 (UTC)
- I think it is ( 1*first_exam + 1/3 * (test1 + test2 + test3) + 1/4 * second_exam) / 2.25
The secret to understanding the solution is that The Major Exam has a weight of 1, each test has a weight of 1/3 and the second exam has a weight of 1/4
Next add up all the weights (taking care to count each "event/test/exam" once) and this will give you the Total_Weight. To get the average, multiply the "items/events/tests/exams" by their weight and then divide by the Total_Weight. 202.177.218.59 (talk) 00:15, 24 December 2013 (UTC)
- Rather than finding fractions of a result, I'd calculate 12 * first_exam + 4 * (test1 + test2 + test3) + 3 * second_exam and divide the total by 27 ... but it's really the same calculation as the two given above. Dbfirs 15:59, 24 December 2013 (UTC)
- See weighted average. StuRat (talk) 17:21, 26 December 2013 (UTC)