A researcher developed the following regression equation to…

A researcher developed the following regression equation to predict muscular strength (y) from fat mass (Fat) in undergraduate students.                                                                             predicted y = 1.0 + 0.7 (Fat)                                                                                           R2 = .49                                                                                    In this sample, what is the proportion of the variance in undergraduate students’  muscular strength that is explained by fat mass (Fat)?

If a researcher was planning a randomized controlled trial t…

If a researcher was planning a randomized controlled trial to evaluate the effect of an exercise intervention (intervention group vs. control group) on blood pressure, in which situation would you need a larger sample size to achieve the same level of power.  Assume all other factors are kept the same.