Howell and Huessy (1981) classified children as exhibiting (or not exhibiting) attention deficit disorder (ADD)-related behaviors in second, fourth, and fifth grade. The subjects were then sorted on the basis of the year(s) in which the individual was classed as exhibiting such behavior. They then looked at GPA for these children when the latter were in high school. The data are given in terms of mean GPA per group.

Exercises 359 Never Second Fourth Second ADD Only Only and Fourth Mean 2.6774 1.6123 1.9975 2.0287 S.D. 0.9721 1.0097 0.7642 0.5461 n 201 13 12 8 Second, Fifth Second Fourth Fourth, Only and Fifth and Fifth and Fifth Mean 1.7000 1.9000 1.8986 1.4225 S.D. 0.8788 1.0318 0.3045 0.5884 n 14 9 7 8 Run the analysis of variance and draw the appropriate conclusion.