Researchers gathered data on cholesterol levels and performance on a stress test on a treadmill from a sample of patients. The mean cholesterol score was 112 and the mean stress test score was 89. The sum of squared cross products for cholesterol and stress test level performance was 523. The sum of squares for the cholesterol tests was 1060 and the sum of squares for the stress test was 980. What was the correlation between cholesterol levels and stress test performance?