"Up about 40 g a week" is a rate with nothing to anchor it: it says the line
slopes without saying where it sits. The sentence now names both ends of the
fit — "roughly 280 g a day then, 400 g a day now" — which is the reading anyone
actually wants from a growth chart.
When the fit is not trustworthy it quotes the average instead, and says the
day-to-day variation is larger than any trend. That difference is the point.
The average is a measurement and survives the noise; the ends of the line are
the line's own output, and quoting them on a fit nobody should read would dress
a guess up as a reading. Everything rounds to 10 g for the same reason — "287 g
a day" would be false precision from four noisy points.
The wording moves into a pure foodTrendSentence() so those rules can be
checked, which is worth doing precisely because they are judgement rather than
arithmetic: the checks now pin that a clear climb gives both figures, a flat run
gives the average and no endpoints, a see-saw gives neither, and nothing is ever
quoted to the gram.
Alexander Heldt
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