4 options: As a physician, you want to discover whether the intake of orange juice influences potassium level in the bloodstream. Is there a difference in potassium by timing (before and after intake)? To test this idea, you select a group of elderly patients from among residents in a nursing home at which previous diet was controlled. You measure each participant's potassium level, provide a pint of orange juice to each participant for the participant to drink over the next two hours, and then measure the participants' potassium levels again. ___________ is the dependent variable in this problem. ___________ is the independent variable in this problem. ___________ is the appropriate statistical test to use for this