Excel is satisfying. The students really learn to do something.

The new concept today was the median. The Wing Aero data showed how misleading the mean could be – giving the CEO a raise raised the mean even though just one salary changed. (We saw that by asking Excel a what-if question.) Then we found the median, and watched it not change.

Moving on to data display: I drew the first bar chart on page 122 on the board, talked about bar charts and labels. Then we had Excel draw the chart for us. The Excel version on the lab macs is not the one on my PC, so I   noodled around to find the features I needed (add titles, change chart type, change colors). That led to a good discussion of noodling – how to find out what your software can do for you. I advised saving drafts often, and told them about the right mouse button.

Homework is to reproduce the charts in Figure 7.2 (page 122).

I postponed the discussion of mode until we’ve done histograms, since it is really only useful for aggregated data of that kind. I hope to get to histograms next week.

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