39. You are interested in further investigating whether there is a causal relationship between stress and sleep quality. а. What type of study design will you choose? Select one: (a) Experimental (b)...

Extracted text: 39. You are interested in further investigating whether there is a causal relationship between stress and sleep quality. а. What type of study design will you choose? Select one: (a) Experimental (b) Quasi-experimental (c) Non-experimental Select one: (a) Retrospective (b) Prospective (c) Cross-sectional Select one: (a) Case-Control (b) Cohort (c) Ecologic (d) Randomized Controlled Trial b. Provide a justification for your selections: c. Identify at least one potential confounding variable. Explain why it may be a confounder and how you might control for it. 40. Answer the following questions regarding sampling method and its relationship to validity. а. What type of sampling method is convenience sampling? Type of sampling method: (a) Probability (b) Non-probability b. How would using a convenience sample affect the external validity of your study? c. How would using a convenience sample affect the internal validity of your study? С.