A medical research team obtained the index of adiposity, basal insulin, and basal glucose values on 21 normal subjects. The results are shown in the following table. The researchers wished to investigate the strength of the association among these variables.

Index of Adiposity Y Basal Insulin (mU/ml)
X1 Basal Glucose (mg/100 ml)
X2 90 12 98 112 10 103 127 14 101 137 11 102 103 10 90 140 38 108 105 9 100 92 6 101 92 8 92 96 6 91 114 9 95 108 9 95 160 41 117 91 7 101 115 9 86 167 40 106 108 9 84 156 43 117 167 17 99 165 40 104 168 22 85 Compute the multiple correlation coefficient and test for significance at the .05 level.