In one high school class, the teacher lets students select their own groups to work on an important class project. As expected, similar students group themselves together. In another class, the teacher randomly divides students into groups, so dissimilar students are often grouped together. Which is likely to be the main advantage of the dissimilar groups over the homogeneous (similar) ones?

a) The dissimilar (heterogeneous) groups will be more cooperative.
b) The dissimilar groups will be more efficient.
c) The dissimilar groups will generate a greater variety of information.
d) The dissimilar groups will have higher morale.

According to the federal regulations, which of the following studies meets the definition of research with human subjects? a study of twenty 4th grade classrooms in which researchers ask the schools to systematically vary the time of day reading is taught, and collect weekly assessments of reading comprehension for each child over a three-month period.the collection of data, by a playground designer hired by the superintendent of schools, about the physical dimensions of school playgrounds, presence of fencing, and the kinds of equipment currently provided.a feasibility study for implementing a year-round school program, focusing on economic issues such a facilities utilization and transportation costs.an analysis of aggregate data comparing statewide high school graduation rates provided by the state department of public instruction, using county tax information.