Did I calculate this correctly?

Every year I make a spreadsheet on Excel with all of my grades for each midterm and test, with the percent allocated to them in the course outline, in order to watch my progress. I’m studying for my very last exam this term, and my spreadsheet seems to be telling me that between just passing the test with a 60% and getting 100%, it’s only a difference of 6 percentage points in my final grade, between an 81 and an 87.

Test 1 (15%): 91
Test 2 (10%): 87
Lab test 1 (15%): 89
Lab Test 2 (20%): 94
Lab test 3 (25%): 71
Final exam (15%) : ??

  1. Did I do my math right?

  2. Do I really have to study? :dubious:

Ok, ok, I’m studying. Really. I swear.

I get the same answer.
This isn’t a math course, is it?

The reason the grade on your final doesn’t seem to matter that much BTW is because it is such a small percentage of your grade. I’ve taken courses where the final accounted for half the grade, that would be a much different situation.
I guess getting a 71 on lab test 3 (25% of your grade) really hurt you. Bummer.

Yes, it really hurt to get that 71. We were using analyzers (it’s a hematology course) and mine went buggy right off the bat because I did my first test wrong, and then I was so nervous about the rest that I made silly mistakes. In the real world, I would have been able to stop, take 5 extra minutes to fix the machine or re-run my test, and kept going. Oh well.

I’ll study and try to get a good grade on this final, to redeem my pride!

The math is really easy.

15% weight x 40% swing = 6% difference in the total.

The difference between 100 and 60 is 40. And 15% of 40 is 6, which is the difference between 81 and 87. So, yes.

Another way to look at it (and the way some of my teachers kept track of final grades) is to assign point values to contributing grades, which add up to a hundred. If you got a 100% on each grade, then you get the full point value. If you scored less than a 100%, then you got a proportional amount of the point value. If completely failed or didn’t do the assigment or take the test, you got no points.

And so, by that method, the point value of the grades of your class would be:

If you got a 100% on each grade, you get the full value of all those points, which equals 100. If you got a 50% on each grade, you points would be: 7.5; 5; 7.5; 10; 12.5; and 7.5 – which equals 50.

So, your final exam contributes up to 15 points toward your final grade. A 100% gives you the full 15 points. A 0% gives you no points. A 60% gives you 9 points (the difference between 15 points for a 100% and 9 points for a 60% is your 6 point difference in the final grade). And teachers are in a work crunch at the end of a semester – no need to go through the motions.

You can see why some teachers give students with an A average going into the final exam a pass from taking the final exam… even if they don’t study and only get a 70% (which would be typical for an A student who didn’t study), it has little effect on the final grade.

For one particular college course I had a 97% average from all tests. The term paper was only 10% of the grade. I decided simply not to do it and took the 0% for the paper and B for the course. Saved me 20 hours work.

If 100% will give you a 87 final grade, a 0% would be 15 points less… a 72. So, no, you don’t have to study if you merely want to pass. But 72s on transcripts look very bad if you plan to do higher ed.


Yeah, but to get a ZERO I’d have to make a concsious effort to answer questions wrong. Like, write “hippopotamus” for every short answer question, and fill in the dots on my multiple-choice computer sheet in a smily face pattern.

I’ll review, and go to bed. A grade in the 60s/70s is just fine for this test, as long as my term mark stays up above 80.

A little off the topic but in answer to (2) I’d say study your butt off and ace the final. UNLESS you know for a fact that your grade is on a straight scale (e.g. 80-89% is a B no matter what).

I helped teach through grad school and come end of semester I’d sit with the prof and noodle out the grading curve. There was always some slop in the numbers and for those people who were on the line between two grades (say an A and a B) we’d look at the pattern. In your case, if you got an A on the final and I was making that call, I’d notice that you had one bad lab score and everything else was high B/low A so you might get the bump to A. On the other hand if you get a low grade on your final then you are solidly in “B” territory and I might also think that your last two scores were low so you were just slacking off a bit.