Answer:
A. Time-Series data
B. Cross-sectional data
C. Cross-sectional data
D. Time-Series data
Explanation:
For Your Understanding:
If the time period is single then use Cross-sectional data.
If their are multiple time periods then use time-series.
A. To determine whether or not the enrollment in higher education is increasing we will use time-series data because enrollment of students is a periodical event and occurs every year. So this means periodic study would be better with time-series data.
B. For comparing the current price of a gallon of gasoline across different gas stations in Los Angeles, CA: we are considering prices in a single time period. Thus the we will use cross-sectional data.
C. For finding see any differences in the average number of calories contained in school lunches served in each of the fifty states on December 1, 2015: we are considering a single time period. Thus we will use here cross-sectional data.
D. To find out the insect population and comparing them with insect population in a geographic region before and after insecticide was used: we will consider two time periods. As the time periods are more than one, hence we will use time-series data here.
