Question: Homework assistance for accounting students. The Journal of Accounting Education (Vol. 25, 2007) published the results of a study designed to gauge the best method of assisting accounting students with their homework. A total of 75 accounting students took a pretest on a topic not covered in class, then each was given a homework problem to solve on the same topic. The students were assigned to one of three homework assistance groups. Some students received the completed solution, some were given check figures at various steps of the solution, and some received no help at all. After finishing the homework, the students were all given a posttest on the subject. The dependent variable of interest was the knowledge gain (or test score improvement). These data are saved in the ACCHW file.

(a) Propose a model for the knowledge gain (y) as a function of the qualitative variable, homework assistance group.

(b) In terms of the β's in the model, give an expression for the difference between the mean knowledge gains of students in the ‘‘completed solution'' and ‘‘no help groups.''

(c) Fit the model to the data and give the least squares prediction equation

(d) Conduct the global F-Test for model utility using α = .05. Interpret the results, practically.