Use the following website to answer these homework questions: https://lakens.shinyapps.io/p-curves/

1.You are working in a research lab to study how people attribute failures to bad luck. Previous research suggests this has a Cohen's d = .20. You will use alpha of .05, power of .80, and a two-tailed test.

a.The lead in the research lab says, "I usually do 30 people per group and that's sufficient power for our study." Do you agree? Why or why not? (Hint: solve for power! What is the Type II error?

b.What methods would you use to tell the lead how to determine sample size for your study? (Hint: think about BEAN and the website!)

c.What is the sample size you need to detect the effect size of interest? (Hint: use the website!)

2.You continue working in the research lab, but now you're studying how people in a bad mood act more aggressively. Previous research suggests this has a Cohen's d = .90.

a.The lead has recognized your infinite wisdom and instead of throwing a random sample size, asks you to calculate what sample size is needed to detect the Cohen's d of .90 assuming an alpha of .05, power of .80, and a one-tailed test.

b.Your lead is shocked at your number. Explain why it's so different compared to your previous study.

c.Your lead asks you if you should use that number suggested by the online calculator because they have the funding and time to test 30 people total. Use the calculator to support your answer. Think about Type I and Type II errors.