Investigators are interested in the relationship between sleep apnea and Alzheimer's disease. In order to more thoroughly understand the relationship, these investigators decide to recruit 50...

Extracted text: Investigators are interested in the relationship between sleep apnea and Alzheimer's disease. In order to more thoroughly understand the relationship, these investigators decide to recruit 50 participants with Alzheimer's and 50 participants without Alzheimer's, and look at their history of sleep apnea. 1) What type of study design is this? Explain your answer in details. 2) What are the explanatory (independent or risk factor) and response (dependent, outcome or disease) variables? Explain your answer.