Fix height vs girth in chapter 5 (modeling)

[Jasper-Wouters]

Hi authors/maintainers,

First of all, thanks for this great resource! I truly enjoyed following this specialization on Coursera.

In the fifth course, Modeling Data in the Tidyverse, corresponding to chapter 5 in the book, I seem to have found a small mistake. i.e.: when analyzing the trees dataset (line 703 and further), girth is used as dependent variable and height as independent, even though we want to infer height from girth and even though the opposite is correctly stated on line 712 ("In this case, since we're asking if we can infer height from girth, girth is the independent variable and height is the dependent variable. In other words, we're asking does height depend on girth?").

I decided to contribute the solution for this, in 2 commits:

• 1 for the correct code
• 2 for some suggestions for the interpretation of the resulting, corrected model

Many thanks in advance for considering this pull request.
Jasper

[Jasper-Wouters]

including potential reviewers: @rdpeng @stephaniehicks @carriewright11 @ShanEllis

[carriewright11]

Hi @Jasper-Wouters, thank you for catching this. We will make these updates shortly.