The director of a training program for a large insurance company has the business objective of determining which training method is best for training underwriters. The three methods to be evaluated are traditional, CD-ROM based, and Web based. The 30 trainees are divided into three randomly assigned groups of 10. Before the start of the training, each trainee is given a proficiency exam that measures mathematics and computer skills. At the end of the training, all students take the same end-of-training exam. The results are organized and stored in Underwriting.
Develop a multiple regression model to predict the score on the end-of-training exam, based on the score on the proficiency exam and the method of training used. For (a) through (k), do not include an interaction term.
a. State the multiple regression equation.
b. Interpret the regression coefficients in (a).
c. Predict the end-of-training exam score for a student with a proficiency exam score of 100 who had Webbased training.
d. Perform a residual analysis on your results and determine whether the regression assumptions are valid.
e. Is there a significant relationship between the end-oftraining exam score and the independent variables (proficiency score and training method) at the 0.05 level of significance? Underwriting
f. At the 0.05 level of significance, determine whether each independent variable makes a contribution to the regression model. Indicate the most appropriate regression model for this set of data.
g. Construct and interpret a 95% confidence interval estimate of the population slope for the relationship between the end-of-training exam score and the proficiency exam score.
h. Construct and interpret a 95% confidence interval estimate of the population slope for the relationship between the end-of-training exam score and type of training method.
i. Compute and interpret the adjusted r2.
j. Compute the coefficients of partial determination and interpret their meaning.
k. What assumption about the slope of proficiency score with end-of-training exam score do you need to make in this problem?
l. Add interaction terms to the model and, at the 0.05 level of significance, determine whether any interaction terms make a significant contribution to the model.
m. On the basis of the results of (f) and (l), which model is most appropriate? Explain.