Lec16 Finishing the 5MV

Announcements

• Lec14 learning check discussion now posted.
• Lec15 learning check discussion
• Problem Set 04 Discussion. Source code file PS-04_discussion.Rmd is available on Problem Sets page.
• Difference between filter() and summarize():
  • filter() merely selects rows without transformation any of the data:
  • summarize() collapses information from multiple rows/observations to create single rows:
  • If we first group_by() to impose a gropuing structure (grey, blue and green in second box) and then summarize(), this collapses information from multiple rows/observations to create single rows on a group-by_group basis:

In-Class

• Slides: arrange() and join
• Section 5.1.5 and 5.3 of textbook

After-Class Updates

• Lec16 learning check discussion