Staff members of a high school newspaper want to obtain an estimate of the average number of years teachers in the state have been teaching. At an educational conference attended by many teachers in the state, the staff members randomly selected 50 conference attendees and asked the attendees how long they have been teaching. Which of the following describes the sample and the population to which it would be most reasonable for the staff members to generalize the results? (A) The sample is the 50 conference attendees, and the population is all teachers in the state. (B) The sample is the 50 conference attendecs, and the population is all conference attendees. (C) The sample is all conference attendees, and the population is all teachers in the state. (D) The sample is all conference attendees, and the population is the 50 conference attendees (E) The sample is the average number of years that all conference attendees have taught, and the population is all conference attendees

For the population, since you are extracting your sample from the conference attendees, then it should be reasonable to use that as your population, because, even though you want information for all the teachers, you dont select teachers randomly, you are making a filter because you pick your sample from a specific group of teachers. For that reason, the average of years teaching obtained from the sample may differ a lot from the real average for teachers, because it is more related with the average for conference attendees.

For example, you may assume that teachers willing to attend a conference are more enthusiastic and, therefore, have more years teaching than a regular teacher. Thus, if you pick a sample from those who attend the conference, your results will be biased and they will show a far greater number than the real average.