The Pew Research Center surveyed a nationally representative sample of U.S.

residents in 2018 and found generational differences in support for expanding the wall along the U.S. border with Mexico, as shown in Figure 3.15. (Millennials were born between 1981 and 1996, Generation X-ers between 1965 and 1980, Baby Boomers between 1946 and 1964, and members of the Silent Generation between 1928 and 1945.)

a. What variables are shown in the figure?

b. Which generation is most supportive of extending the border wall between the United States and Mexico? Which is the least supportive?