The correlation coefficient for practicing violin and getting better grades in a group of people is 0. 8. Analyze the following statement: Playing violin causes students to get better grades. Is this a reasonable conclusion? Yes; students who play violin must necessarily get better grades. Yes; the correlation coefficient is above 0. 5, so that implies causation. No; playing violin and earning better grades are completely unrelated. No; even though there is a strong positive correlation, playing violin doesn't cause students to get better grades.