Started class with an apology for mangled problem 7.13 on the homework – I need straighten that out on Thursday.

Talked about the term paper – topic possibilities next week, then an outline, then a draft – “so no reason why you can’t all earn A’s”. Advised that complex political or scientific subjects (global warming, the influence of money on politics) are too complex for this course. The same is true for most quantitative questions from the sports pages – I got to define hot stove league.

Things not to do in Excel: fake 3d, and pie charts. Here’s a link to a posting on why they are a bad idea, and a link from that link.

The meat of the day: histograms. They’re a kind of bar chart. Defined the mode – and pointed out that it’s really useful only for summarized data. (In the Wing Aero dataset it’s either 250 or 25, depending on how the data are sorted!)  Talked about bell curves (symmetrical) and skewed – like income distribution. There mode < median < mean.

Then on to how to compute from histograms. Mode is easy – it’s the highest bar. Got started on the mean, but didn’t have enough time. Will start the next class there. It’s the first opportunity to copy formulas in Excel and see the automatic increments on cell references.

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