Angel, the course management system, calculates an overall grade in real time. This is good, but it means that as new components of the final grade come in, some grades adjust downwards. This generates a lot of email traffic. This is my generic explanation of what just happened.

I just released two new sets of grades. First, **the attendance grade**. Students have to be at nine pop quizzes to get this (worth 10% of final grade). We have now done nine, so regular attenders just got their 10%; those who have yet to be at nine just got a zero. They will get their 10% when they hit nine quizzes (and there will at least three more before end of semester). But for now, that means those who have missed any pop quizzes had their score go down by 10%.

Second, I added the** extra credit** for those students who went to the antibiotic class last week. That’s 3% added to final grade, but since we have done just 80% of the course to date, that’s right now appearing as a bit more than 3% (3/80 instead of 3/100).

Of course **the overall grades being returned right now are far from settled**. There is still another class test to go, and since I take the best two of the four tests, the class test score can still rise (but not fall). There is still another blog period to go, and since I take the best period from the three, the blog score can rise (but not fall). And the final exam is worth 20% (and so when those scores are released the overall grade can rise or fall). Students: if in doubt, the grading algorithm is on p.3 of the syllabus.