There is a linear relationship between the calorie content and protein content of food items sold at a restaurant. When a regression equation is constructed to predict a food item's calorie content based on its protein content, the regression equation is found to explain 42% of the variability in calorie content. This means that the correlation, or r, between calorie content and protein content, must be equal to approximately what value? Choose the answer below that most closely matches your calculations. Group of answer choices 0.65 0.42 Less than 0.10 0.21 0.18