The material covered in Week 8 is a review of your prior course in statistics and the earlier weeks in this course. I would like you to use the Discussion post and reply this week to clarify any confusion you have about association claims, correlation coefficient, and the four types of validities applied to studies with association claims.

For the Week 8 Discussion post, please complete the following instructions:

1).  After Reviewing the week 8 material, which of the concepts are still unclear to you? Please post a specific question you have based on the Week 8 material. This should not be a question that is answered with a simple yes/no or with a basic definition from the text. It should be an application to a specific example or a broader question about the material.