Answer
$L=33.5n+527.5$
the slope is $33.5$ (pages) per (edition increment).
(For each new edition, the number of pages increases by $33.5$ pages.)
.
Work Step by Step
Using desmos.com, we enter a table (columns labeled as $x_{1},y_{1}$), enter the data points, and in a new cell, enter$\quad y_{1}\sim mx_{1}+b$
The calculator returns $\left\{\begin{array}{l}
m=33.5\\
b=527.5\\
r=0.9435
\end{array}\right.$
where
$m=\displaystyle \frac{n(\sum xy)-(\sum x)(\sum y)}{n(\sum x^{2})-(\sum x)^{2}}\qquad b=\frac{\sum y-m(\sum x)}{n},$
and the $r$ is the regression cofficient
$\displaystyle \quad r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{n(\sum x^{2})-(\sum x)^{2}}\cdot\sqrt{n(\sum y^{2})-(\sum y)^{2}}}$
$r$ is close to 1, indicating a good fit for the data.
Replace
$x_{1}\leftrightarrow n$, the independent variable,
$y_{1}\leftrightarrow L$,
The regression line is given by
$L=33.5n+527.5$
$b.$
The unit of slope in
$y=mx+b$
is (unit of y) per (unit of x)
Slope is calculated as (change in y)/(change in x).
Here, $L=33.5n+527.5$
the slope is $33.5$ (pages) per (edition increment).
(For each new edition, the number of pages increases by $33.5$ pages.)
