Minimize/optimize package dependencies

[briatte]

• [ ] Choose between moments and e1071
  • [ ] Only mention e1071 and its alternative measures?
• [ ] Session 9
  • [ ] Use ggeffects or marginaleffects -- or both? use in more than one session?
• [ ] Session 11
  • [ ] Replace car with anything that plots scatterplot matrices?
  • [ ] Remove corrr entirely?
  • [ ] Remove ggcorrplot entirely? (or find a package that does the same, plus scatterplot matrices?)
  • [ ] Keep factoextra and ggfortify
  • [ ] Find a way to re-use plotly? e.g. https://plotly-r.com/d-charts.html -- or remove entirely
• [ ] Session 12
  • [ ] Install sf earlier and have a map in Session 3
  • [ ] Replace life expectancy example from Session 12 with more complex example?
  • [ ] Add a full-fledged network example to justify installing igraph and ggraph?
  • [ ] Add a full-fledged dynamic document example using modelsummary (and possibly texreg)?
  • [ ] Make pdftools optional (only recommend it in the slides?)
• [ ] Extras
  • [ ] Provide an additional example using rvest?
  • [ ] Keep WDI, but use it more than once? -- see #21
  • [ ] Modify exercise-04 to use WDI but save the data
  • [ ] Modify life-expectancy to use WDI and save the data

Checks:

• [ ] Check that countrycode is used in multiple sessions
• [ ] Check that broom is used in multiple sessions
• [ ] Check that ggmosaic is used in multiple sessions
• [ ] Check that ggrepel is used in multiple sessions, "", "", "",
• [ ] Check that performance is used in multiple sessions
• [ ] Check that texreg is used in multiple sessions