Answer the following questions using your own words. I 1.a What are some advantages and disadvantages in the use of a posttest-only control group. design versus a pretest/posttest-control group.design?-(Must identify at least one advantage. and one disadvantage per design-so four total). I ANSWERT One of the unique strengths of the posttest-only control group design is its ability to safeguard against the reactive effects of testing and treatment or contamination from extraneous factors owing to repeated measures. In other words, it excludes the potentiality of pretest-treatment interaction given that the- outcome variable is measured only once. A major weakness of this design is there is no way of knowing whether randomization truly safeguards against the initial differences between groups. One of the- advantages of the pretest/posttest control group design is that it allows the researcher to assess the- equivalency of the groups prior to application of the treatment. However, a key problem with this design is that there is a possibility of testing effect, that is, the pretest measurement may influence the posttest scores. In other words, it is possible that using the pretest may sensitize the participates to the treatment- and hence render the treatment less effective or more effective than it would have been without the- pretest. 2.0 What is a confound and how is it related to internal validity? Da ANSWERT A confound is an uncontrolled extraneous factor-or flaw that distorts the true relationship between's exposure and outcome. The confound is related with both exposure and outcome-but not part of the | causal pathway. Because internal validity denotes how accurate the estimation of the link between's exposure and outcome is, presence of a confounding variable-limits or threatens internal validity D 3.0 What is the relationship between external validity and the college sophomore problem?Do ANSWERS External validity refers to the extent to which the findings of a study can be generalized across multiple - populations. In the college sophomore problem, most studies in psychology are carried out using subjects college students, especially freshmen and sophomore, which is scarcely-a representative sample from the general population. The college sophomore problem is thus an example of how external validity off research can be limited.04.0 On the most recent exam in your biology class, every student earned an A. The professor claims that he must really be a good teacher for all of the students to have done so well. Given the confounds discussed this week, what alternative explanation can you offer for this result? (Don't just list a concern-briefly provide a justification). I ANSWER-T Prior knowledge of the biology topics taught by the professor. This variable is likely to influence the students' grade irrespective of the professor's teaching style. Before the professor can make his claim, he"should-divide the students into two-groups, experimental and control group. The experimental group should have knowledge of a topic that the control group doesn't possess. If the two groups score similar grades in an exam, then it can be ruled out that prior knowledge of a biology topic is not a confound. O 5.0 A health magazine recently reported a study in which researchers claimed that women who take iron supplements have better problem-solving abilities. .Further investigation revealed. that they assessed problem-solving abilities in a group of women and then had the women. self-report whether or not they take iron supplements. Discuss one potential threat to. internal validity as it relates specifically to this study. ANSWER-1 Self-report-data may affect the internal validity of the study in several ways. First, the women may's respond to the questions in ways that-cast a positive light on them. For instance, many of the women may" claim to be good at problem-solving abilities to appear desirable. Secondly, the women may's provide inaccurate information due to poor recall. For instance, the women many not remember the frequency of taking iron supplements.0