Chapter 49 19. Reflection questions

1. Why is long-format data usually easier to plot with ggplot2?
2. Why should we check join keys before merging datasets?
3. What is the difference between an NA value and a true zero?
4. Why is it important to document assumptions when cleaning dates?
5. What are the risks of randomly imputing missing values?
6. Why might postal codes need standardization before joining datasets?