. A study was conducted to investigate whether or not exercise is a factor in the overall outlook and positive spirit of Denton County residents. For the study, 400 Denton County residents were selected at random from each of the following two categories: those who exercise on a regular basis and those who do not. For the purpose of this study, the term regular exercise was well defined for all participants. A total of 800 people completed a brief telephone survey. Of those who exercise regularly, 74% said that their overall outlook on life was positive. Of those who did not exercise regularly, 68% said that their overall outlook on life is positive. Though not a definitive study, the researches concluded that exercise does appear to influence the attitudes of Denton County residents. In addition, the researchers estimated that approximately 71% of all Denton County residents have a positive outlook. Further research will likely be conducted on the subject at a later time. Answer all of the questions below. (4 points each)

a. What population was this study designed for? What sample was used for this study?