(7 points) A researcher wants to study the relationship between the academic achievement (as measured by cumulative undergraduate GPA) of all first-time, full-tim college freshman at Oklahoma public universities who have completed their freshman year coursework and their high school GPA, number of college-prep courses taken, mother's education, family household income. The researcher has gained access to data on all approximately 50,000 students attending OU, OSU, and SE and SW OSU, and UCO who meet the above criteria. a. What is the population? What is the sample? Remember, be as specific as possible. b. Identify the variables that are to be used in the study and indicate whether or no they are dependent or independent variables. c. If we were to substitute the variable "college academic achievement" in the researcher's study for a variable instead measuring "college persistence" (as defined by not dropping out their freshman year [yes or no]), how does that change the type of variable to be used for our study? Please explain