A study about hypertension found that the percent of the population with hypertension increased increased as a person got older (as they aged). What is the INDEPENDENT variable in this scenario? The graph below shows the results from this study Prevalence of Hypertension in US Adults during 2013 to 2016 100 80 60 Percent of the Population 40 20 0 20 40 30 90 70 80 50 60 Age (years) 1) age 2) percent of population with hypertension 3) hypertension 4) people