Final answer:
Without the specific data or the cited study from the textbook mentioned in the question, it is impossible to provide a direct answer regarding the proportion of very aggressive adolescents who drop out of high school.
Step-by-step explanation:
The direct answer to the question regarding the proportion of adolescents who were very aggressive when they were younger and drop out of high school before graduation is not explicitly provided in the information given. Without specific data or a study citation from the textbook mentioned in the question, it is not possible to give an accurate answer. To assess factors related to high school dropout rates, it is important to look at comprehensive studies which consider various factors such as aggression, family background, socio-economic status, and educational support.
One could cite studies and statistics similar to the provided data. For example, the claim that 14 percent of all public school children dropped out of school in the 1980s, and higher rates among minority students, which indicate a significant relationship among socio-economic factors and dropout rates. Additionally, factors such as being the victims of bullying with 27.8 percent reporting such instances, or the lack of support programs like bilingual education could influence dropout rates. However, linkage to aggression and dropout is not directly established with the information given.