In a study involving a large random sample of high school students, an educational psychologist observes a correlation of r = 0.78 between GPA and the number of missed school days. If the relationship is linear and we want to predict GPA based on the number of missed school days, which variable should go on the horizontal (or x) axis of the scatterplot? O Number of missed school days, because it is the explanatory variable. O When conducting a regression analysis, it makes no difference which variable is on which axis of the scatterplot. O Number of missed school days, because it is the response variable. O GPA, because it is the response variable. O GPA, because it is the response variable