Question

a)A psychologist is planning a study on the effect of motivation on performance on an attention task. In this task, participants try to identify target letters in a stream of letters passing by at a rapid rate. The researcher knows from long experience that, under ordinary experimental conditions, the population of students who participate in this task identify a mean of 71 of the key letters, that the standard deviation is 10, and that the distribution is approximately normal. The psychologist predicts that, if the participant is paid a dollar for each letter identified correctly, the number correctly identified will increase to 74. the psychologist plans to test 20 participants under these conditions, using the .05 level. What is the power of the study.

(write your answer to two decimal places).

b)A study placed strangers in pairs and asked them to talk together following a series of instructions designed to help them become close. At the end of 45​ minutes, individuals privately answered some questions about how close they now felt to their partners.​ (The researchers combined the answers into a​ "closeness composite.") One key question was whether closeness would be affected by either​ (a) matching strangers based on their attitude agreement or​ (b) leading participants to believe that they had been put together with someone who would like them. The result for both agreement and expecting to be liked was that​ "there was no significant differences on the closeness​ composite." The researchers went on to argue that the results suggested that there was little true effect of these variables on closeness. An excerpt has been linked below. Explain this result to a person who understands hypothesis testing but has never learned about power or effect size. Here is the excerpt: "There was about​ 90% power in this study of achieving significant effects . . . for the two manipulated variables if in fact there were a large effect of this kind (dequals​0.8). ​Indeed, the power is about​ 90% for finding at least a​ near-significant (pless than​0.10) medium-sized effect (dequals​0.5). Thus, it seems unlikely that we would have obtained the present results if in fact there is more than a small effect. . . ." Choose one of each of the underlined words by taking them The power of a study represents the likelihood of getting a statistically (a) significant/nonsignificant result in your​ study, if in fact the research hypothesis is (b) true/not true. Effect size can be thought of as the degree to which populations (c) overlap/do not overlap. The (d) larger/smaller the effect size​ is, the greater the power will be. Given this​ study's (e) low/high level of power for detecting large and​ medium-sized effects, the researchers were able to conclude that the most likely reason for the nonsignificant study results is that the research hypothesis is (f) true/false.​Thus, it is (g) likely/unlikely that the results of the study would be nonsignificant if there were a medium or large effect in the population. What is a,b,c,d,e,f,g

Answer 1