=+Three hundred twenty-two subjects, selected at random from those who successfully participated in a program to quit smoking, were weighed at the beginning of the program and again 1 year later. The mean change in weight was 5.15 lb, and the standard deviation of the weight Specimen Direct Stratified Specimen Direct Stratified 1 24 8 2 32 36 3 0 8 4 60 56 5 20 52 6 64 64 7 40 28 8 8 8 9 12 8 10 92 100 11 4 0 12 68 56 13 76 68 14 24 52 15 32 28 16 0 0 17 36 36 18 16 12 19 92 92 20 4 12 21 40 48 22 24 24 23 0 0 24 8 12 25 12 40 26 16 12 27 40 76