Questions 7 to 9 refer to the following research situation: A researcher who wanted to determine the benefits of using a new algebra study technique obtained permission from a school district to select 50 high school students. The researcher selected 50 students at random. The researcher selected 25 of these 50 students to participate in the new study program. The researcher gave a training session on traditional study techniques to the other 25 students and asked them to use these methods.