3. [6 points] D Two social scientists are debating the merits of the Perry study. Research A says the results may suffer from bias due to a form of the placebo effect: graduates of the Perry preschool are proud of their association with the school and the famous study of it, and they may put a positive \"spin\" on their responses to researchers' questions, or fail to report embarrassing life events. Researcher B says the ndings are protected from that and other sources of bias because of the fact that the study used unbiased methods of estimation, such as estimating its effect on high school graduation by taking the difference of proportions of treatment and control members who obtained a high school diploma. Who's right? (a) Can the scenario Researcher A is concerned about accurately be described as a situation in volving \"bias\"? Say yes or no, stating relevant qualifications or limitations to the meaning of \"bias- (b) Is Researcher B making a defensible claim when he says that the combination of the research design and the statistical methods are \"unbiased\"? Say yes or no, stating relevant qualica- tions or limitations to the meaning of \"unbiased.\" (For the purpose of answering this question, assume that there treatment assignment was completely at random and there was no loss to follow-up.)