Based on data from the U.S. Census Bureau, a Pew Research study showed that the percentage of employed individuals ages 25–29 who are college educated is at an all-time high. The study showed that the percentage of employed individuals aged 25–29 with at least a bachelor’s degree in 2016 was 40%. In the year 2000, this percentage was 32%, in 1985 it was 25%, and in 1964 it was only 16% (Pew Research website). 

a. What is the population being studied in each of the four years in which Pew has data? 

b. What question was posed to each respondent? 

c. Do responses to the question provide categorical or quantitative data?