A cohort study followed 850850 adults for 33 years to evaluate whether habitual daily coffee intake is related to average nightly sleep duration. Coffee intake was measured as "at least 33 cups per day" versus "fewer than 33 cups per day". The investigators reported that high coffee intake was associated with shorter average sleep duration. What is the response variable, and what is the explanatory variable in this study?

Response variable: Average nightly sleep durationExplanatory variable: Coffee intake category

Response variable: Cohort membershipExplanatory variable: Coffee intake category

Response variable: Average nightly sleep durationExplanatory variable: Age of participants

Response variable: Coffee intake categoryExplanatory variable: Average nightly sleep duration

A cohort study followed 850850 adults for 33 years to evaluate wh...

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