The significance of family background (FB) and school factors (SO) in predicting differences among students in their achievement and motivation in different regions of the country (North-South) and areas of residence (metropolitan-nonmetropolitan) is investigated. A statistical test of the equality of slopes and intercepts was used for the FB and SO sets combined to determine group differences, and commonality analyses were conducted and compared for the different groups to determine the relative roles of FB and SO. Analyses showed that Expectations for Excellence, Educational Plans, and Study Habits were more fully explained by FB and SO in the South than in the North, except at grade 12 where the North or the metropolitan North becomes more predictable. Attitude Toward Life and Achievement were more predictable in the South than North from FB and SO for all grade levels. Family background plays a more significant role in the development of achievement and motivation than do the school factors, and is generally more influential in the North than in the South for all dependent variables except Educational Plans. School factors are slightly more influential in the South, as are the common portions, which may represent mutual interplay of FB and SO. These results suggest that independently of an individual student's own family background, the achievement and motivational levels of his fellow students influence his achievement and motivation. See TM 000 144 and TM 000 145. (PR)