A sociologist wants to investigate the question, "Is there a relationship between texting during class and grade- point-average (GPA) among high school seniors in a large district?" Which study design is most appropriate? Before the semester starts, randomly select 40 seniors from each high school who do not text during class. Assign 20 to the texting treatment group (text three or more times during every class meeting) and 20 to the control group (no texting during class). At the end of the semester, obtain each student's GPA from the appropriate admissions and records office. Compare the GPA of students who routinely text during class to the GPA of students who do not text during class. Obtain the cell phone numbers of all seniors in the district. Send a text survey to each student asking about the student's texting habits during class. Obtain each student's GPA from the appropriate admissions and records office. Compare the GPA of students who routinely text during class to the GPA of students who do not text during class. Obtain a list of seniors in the high school district. Randomly select 300 seniors and survey them about their texting habits during class. Obtain each student's GPA from the appropriate admissions and records office. Compare the GPA of students who routinely text during class to the GPA of students who do not text during class.