Answer
$(C)$
Work Step by Step
The average rate of change of $f$ over the interval $[a, b]$ is given by:
Average rate of change of $f\displaystyle \ \ =\frac{f(b)-f(a)}{b-a}$
The units of the average rate of change of $f$ are units of $f(x)$ per unit of $x$.
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Over $[3,10]$, the average rate of change for $f$ was
$\displaystyle \approx\frac{1.00-1.42}{10-3}=\frac{-0.42}{7}=-0.06$
and for the regression line, about
$\displaystyle \frac{0.98-1.40}{10-3}=\frac{-0.42}{7}$
Thus, we choose ($C$)
