Plan: electricity bill and linear equations in Excel – can I reestablish momentum or will I have to do averages from histograms for the third time??
Well I seem to have done it. I wonder whether I’m dreaming.
Started with the Tamworth electricity bill – deliberately postponing any discussion of what a kilowatt-hour actually is, other than “the units with which we measure the amount of electricity). Maybe I’ll talk about energy and power Thursday, or next Tuesday. Exam a week from Thursday.
We talked through several examples of “fixed cost + rate*(variable amount) with units, connected this to y=mx+b from hated algebra. Prepared a table of values for Tamworth and drew a graph (by hand, on the board). Then redid the computations in Excel. Important ideas (lots of them): scatter plot, not column chart. (Not line chart either.) Using X$Y to prevent Excel from incrementing row index when copy/pasting. Then did a second electricity bill plan with different fixed cost (intercept) and rate (slope), used $XY to prevent Excel from incrementing column index.
I will add one homework assignment on this material – a test as to whether I went too far.
There’s an exam a week from Thursday.
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