20150210 Halpin weighted grades

From Richard Halpin 2/10 9:58a:

I have a faculty member who is currently testing Canvas and has concerns about how the weighted grades are coming out in the running total. She has calculated them manually and they are a couple of points different in all cases.

The course in question is 2151DHBS3202-100

We have number of exams collected into an assignment group and that group is worth 60%% of the total grade. Now they have taken one exam the faculty has calculated what the running total should be and it is not the same as what is displayed in Canvas.

This is causing some serious concerns for the faculty.

The strange thing is that come of the student grade seem similar to Canvas when calculated manually and others are over 1% away.

I have looked online and I can’t find any information about how Canvas calculates its running totals for weighted grades. I did find many long forum discussions about how poor people thing the Grade module is in Canvas and how they had similar concerns about its ability to calculate grades with accuracy.

I am hoping you know (or can reach out the Canvas and obtain) an explanation about how the grades are calculated here and why they may be different from the faculty calculation.

As an example, in the Gradebook on the course the faculty has entered the results for 4 students for Exam 1 so far and Canvas is calculating the Total. Her own calculations for these four students come out as 85.68, 101.59, 94.97 and 90.79 whereas Canvas is showing 86.7, 104.4, 95.6 and 93.3.

Hoping you can help

Investigation:

Logged in to canvas, went to 2151DHBS3202-100, grades, saw first four students had four total grades.

Response:

From what I can see, Canvas is calculating the grades correctly.

Semester review is 10% of final grade, Exams 1-3 is 60% of final grade, and Final Exam is 30% of final grade.

HOWEVER, Final exam has a null value.
Therefore, for the first row, 83.7 is 10% of the final grade, and 86.7 is 60% of the final grade.

Since this does not add up to 100%, the first column is actually 14.2857% of the final grade, and the second column is 85.7143% of the final grade:
100/(.7/.1) = 14.2857% and 100/(.7/.6) = 85.7143%
Taking the grades:
(83.7*0.1428571) + (86.7*0.8571429) = 86.27143, which is the displayed value.
You can check the other values yourself to confirm my math.
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