Kai, a seventh grader, wants to determine the average number of times the families in his neighborhood visit the pool during the summer. He samples the families of four of his classmates. Which improvements could Kai make to his sample to increase the validity of the results? Select three choices.
B
sample families that have children who are not in seventh gradeC
sample families that regularly use the poolD
sample families whose answer to the survey question is predeterminedE
sample families living in every third house in the neighborhood