What is the critical value of r for testing these hypotheses if ?=.05? What is the simple, bi-variate correlation of hours studying (x) and quiz score (Y)? What is the partial correlation between hours studying (x) and quiz score (Y) controlling for material difficulty (z)? How would you write up this result?

Imagine you have a record of how many hours you've spent studying each week in one of your courses (X), and also your scores on the end of week quizzes (Y). You think your studying has been effective, but you are also worried that you might just be spending more time studying on weeks when the material is easy and the studying isn't that difficult. You ask a classmate to rate how difficult each week's material has been (Z). You want to see if the positive correlation between your hours studying (X) and quiz score (Y) is still significant after partialling out their relationship with the material's difficulty (Z). You have the following data: Dataset A H W N O W X UAAHAWN