Plan: answer questions about regression. Start exponential growth. I hope the changed tone I felt in the last class continues – some of the failing students have dropped the course and we’re in a kind of countdown to the end of the semester. Let’s try to finish on a high.

What happened:

I enjoyed the class – I hope the students did. I hope it was interactive enough – I worry that I talk too much. I will try to plan a Thursday class that calls for some group work.

I started with a reprise on correlation-vs-causation, and added this question to their homework:

 Find a newspaper or magazine article or web posting where someone says “THIS happened because of THAT”. Write about whether the “because” is reasonable – is the author leaving out important other factors? Might the “because” really go the other way? Is there some behind-the-scenes reason the author has for making this connection?

If you can, find an example where the author’s argument depends on interpreting numbers, so that it’s really a question about
quantitative reasoning. But that’s not the most important part of the exercise. What really matters is that you think and write about the difference between correlation and causation. (This is something you might have to pay attention to in your term paper, too).

Then we started exponential growth. The spreadsheet was very useful – I think it made clear both the formula (=START*RELCHANGE^A<n>) and the recursive computation (=RELCHANGE*C<n-1>) . This was the first introduction to named cells in a spreadsheet. (I think this idea could serve someplace as a good way to teach algebra – start with the spreadsheet and move to pencil and paper rather than the other way around. Cells are really variables.)

 

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