Valentine’s Day. Can I find an inflation problem for the occasion?
Didn’t have time to try flipping the class last week, so will have to promise it again today for next week – inflation. (I don’t think it would do to try it first for Excel.)
(Note – never got around to blogging last Thursday’s class.)
What happened:
I spent most of the time working the problem from CSM on book sales increase of 3.9% to $12b. Two wrong solutions (subtract 3.9%, which does give a reasonable answer, though wrong, and divide by 3.9, which doesn’t). Then someone suggested dividing by 1.039. Hooray for the method.
The last part of the question asked if Alex Beam’s “The book is 20 times better than the movie” is really a quantitative statement. I said not – and one student suggested comparing the Amazon book rating (up to 5 stars with a half a star increment) with the IMDB movie rating (up to 10 stars?). So I think I’ll put that in the book.
Spent half a class on inflation, mostly with the meaning of the term and the BLS inflation calculator. Interesting comparisons with a century ago.
We worked an example showing why 10% inflation for each of two years wasn’t 20%, but more: 1.1*1.1=1.21. A student asked how to compute the annual inflation rate that would produce (say) 10% inflation in five years. It was the end of the class and I botched the discussion, which I intended would lead to solving (1+x)^5 = 1.1 by cut and try.
Meeting Thursday in the Mac Lab for the first time, since the exam is there next Tuesday.
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