An online retailer uses the number of website clicks to predict sales revenue for an online hair-replacement (wig) company. the r² statistic represents? a. the percentage of variance in the predictor (clicks) variable accounted for by the outcome (sales revenue) variable. b. the proportion of variance in the outcome variable (sales revenue) accounted for by the predictor variable (clicks).c. the proportion of variance in the predictor variable (clicks) accounted for by unknown variables. d. the percentage of variance in the outcome variable (sales revenue) accounted for by unknown variables.