Class 17 – Tuesday Nov. 2, 2010

By popular request, worked Exercise 7.17: the Physics department has nine male professors making $90K each and one female professor making $100K – perhaps because they were required to act affirmatively and women physicists are in demand. The English department has 8 women making $50K and two men making $40K. We found all the averages: mean, median and mode, overall and by department and by gender. The women are paid more than the average (mean) in each department and less than the average overall.

One student asked for help remembering the names for the kinds of averages. So we talked about mnemonics. Nick Sullivan suggested “there are mo’ of those than anything else.”

Getting ready for the exam, reviewed what Excel can do for you:

In the last 15 minutes, started on linear functions (not o n Thursday’s exam). Read the Tamworth electricity bill, talked a little about kWh and leaving the light on, checked the calculation there. Showed how the pattern

fixed amount + (amount per unit)*(number of units)

works in various situations: truck rental, cell phone bill, limousine rental (the variable part is the late return charge), salesmen working (partly) on commission.


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