Your lab write-ups make up about 70% of your overall grade,
and the quizzes
make up the remaining 30%.
Click here for a point breakdown of all the points on all the labs (pdf).
To calculate your overall grade you will need to determine
your lab average
and your quiz average, then calculate
an overall weighted average.
Determine your lab average
1) Add up all the points you've gotten on the lab write-ups (pre-lab,
lab report, discussion questions, post-lab, and unknown summary sheets).
2) Divide by the total number of points possible.
Experiments 1, 5, 6, 9, and 10 are worth 55 points each.
Experiments 2, 3, 4, 7, and 8 are worth 75 points each.
3) Multiply by 100.
Determine your quiz average
4) Drop the lowest quiz score so far and add up the others.
5) Divide by the total number of points possible (20 for each quiz kept).
6) Multiply by 100.
Calculate your overall grade
7) Multiply your lab average by 0.7
8) Multiply your quiz average by 0.3
9) Add them up. This will give you a number between 0 and 100, which is your percent for the course. Letter grades are assigned on a 90 / 80 / 70 / 60 basis.
After Week 4, Alice wants to calculate his grade. These are his scores so far:
Experiment 1: Pre-Lab 4.5, Report/Discussion 28, Post-Lab 8
Experiment 2: Pre-Lab 4, Report/Discussion 35, Post-Lab 7,
Unknown Summary Sheet 14
Experiment 3: Pre-Lab 4, Report/Discussion 34, Post-Lab 6,
Unknown Summary Sheet 20
Experiment 4: Pre-Lab 5, Report/Discussion 39, Post-Lab 10,
Unknown Summary Sheet 17
Quiz 1: 20 Quiz 2: 16 Quiz 3: 10 Quiz 4: 14
Calculating the lab average: Alice adds up all the points he has earned on the lab reports so far and gets 221.5. The first four labs are worth a total of 280 points (55+75+75+75), so his lab average is (221.5/280)×100 = 79.1%
Calculating the quiz average: Alice throws out the lowest score
(a 10 on Quiz 3) and adds the rest to get a total of 50 for the three remaining quizzes. Three quizzes are worth a total of 60 points, so his quiz average is (50/60)×100 = 83.3%.
To calculate an overall grade, Alice multiplies his lab average by 0.7 and his quiz average by 0.3 and adds the results:
79.1% × 0.7 = 55.4
83.3% × 0.3 = 25.0
55.4 + 25.0 = 80.4%
Alice is running a low B at this point in the course.
These calculations do not take into account the TA's safety/technique evaluation points. If Alice has been coming to lab prepared and on time, has been dressing appropriately, and hasn't been a problem for his fellow students, he has been earning an additional 3 points each week. That's enough to bump his lab average up to 80.0%, and his overall grade to an 81%. But if he habitually shows up late, unprepared, or wearing shorts and sandals, he has been losing those 3 points each week, his lab average will be only 75.9% (221.5 points out of a possible 292), and his overall grade will be only 78.1%.
In addition to the safety/technique evaluation, your TA will give you a notebook grade when you turn in your lab notebook at the end of the semester. This is worth 8 points toward your lab grade. All told, the lab portion of the class adds up to a total of 685 points over the course of the semester. The notebook grade is 1.2% of your overall lab average, and the safety/technique points are a total of 4.4% of your overall lab average.
If you have any questions about how grades are calculated, feel free to ask your TA or Dr. Anderson.
Click here for a printable version of this page (in PDF format).