Data indicate that infants with low birth weight tend to lag behind normal infants in terms of their general development - muscle strength, alertness, visual attention and tracking. The following data are infant birth weights and their scholastic achievement scores at age 10 for a randomly selected sample of n = 12 children: Birth Weight 81 96 132 104 122 88 127 108 Scholastic Achievement 58 65 78 76 81 62 81 85 76 86 113 110 55 68 79 72