Case Study: U.S. Births

(Section 8.3)

US Births

Leran about Births78 in the mosaicData package:

library(mosaicData)
?Births78
View(Births78)

Old Scatter Plot

ggplot(Births78, aes(x = date, y = births)) + 
  geom_point() +
  labs(x = "Day of the Year", y = "Number of U.S. Births",
       title = "Daily U.S. Birth-Numbers in 1978")

Some of the days have significantly fewer births. What’s going on?

A Hunch About What’s Going On

Are there fewer births on weekends? Try this:

New Variable

This new variable says whether or not a day is at the end of the week:

New Graph

Investigate the Exceptions

What do you notice?