Video: “Exponential growth and epidemics”

Here is a 9min video that I highly recommend you watch:

You can get a lot out of just watching the first minute: watch how he steps up the graph of the # of COVID-19 cases (outside mainland China) from Jan 22 to March 6, and shows that C(n+1) ≈ 1.2*C(n), i.e., we’re seeing exponential growth with C(n) = C(0)*(1.2)^n. Note that he has the advantage that he can just “zoom out” to redraw the scale of the y-axis.

After that initial segment, he starts discussing some parameters relevant to the topics of our course (“E = Average number of people someone infected is exposed to each day,” and “p = Probability of each exposure becoming an infection”).

Also starting at around 1:50 mark, he shows what a logarithmic scale is, and why it’s useful for graphing exponential growth curves–they turn into straight lines on a log scale! And then he does a linear regression, and shows the R^2 (the coefficient of determination!)

Distance Learning Update: 1st official Blackboard Collaborate session TODAY

Hopefully you have been receiving the Blackboard annoucements via email. For now, I will also post them to OpenLab:


Hi all,

I will plan to have Blackboard Collaborate Ultra sessions during our regularly scheduled class times. So our first one will be today (Monday) from 12p-1:40p. You should be able to see the session scheduled under Course Tools->Blackboard Collaborate Ultra in Blackboard. You can join the session there, or via the guest link:

https://us.bbcollab.com/guest/19342ee95c5d4e8a80a6886e4b5cfd21

Attendance (i.e., logging in) for class sessions is not required, but I do strongly recommend it, assuming you have access to a device and a reliable wifi or data connection. As some of you saw last week, you can even join and view these sessions via a phone (but I do recommend a computer or tablet, so that you have a bigger screen to view pdfs, the whiteboard and other content that I will share in the sessions).

Tomorrow we can go over any remaining HW5 questions, and discuss conditional probability (using the Class 12 outline pdf I uploaded to Openlab on March 11):
https://openlab.citytech.cuny.edu/groups/math1372-ganguli-spring2020/files/

For those of you that can’t join, I will post a summary and followup instructions on OpenLab this afternoon after the Blackboard session.

Hope to see all of you on Blackboard!