In last week's lab, we looked at a 2007 study that was published investigating the effectiveness of three different homework methods (checking figures at various steps in the solution, a full solution and no solution) in students' learning outcomes, i.e. assisting students to learn the course material.

This year, researchers wondered if the way the homework method was presented, in person or online, might also be a factor in the improvement in the grades (the difference in the posttest and pre-test score).

Students were randomly assigned to a treatment group, and the difference was found between their post-test and pre-test score on the topic.

At the 5% significance level, can you conclude that Homework Method and Presentation Method interact in their effect on mean improvement score?

a. In the context of the problem, identify each of the following:

?Response Variable:

?List the factors (explanatory variables) and name the levels of each factor:

?Number of treatment groups:

b. Is the Additive Enough Condition met? Explain, referring to the interaction plot included on the Minitab output. Note that all the other assumptions were checked, and are met.

c. Which of the following is the correct hypothesis for this question?

1. Ho: There is an interaction effect between Homework Method and Presentation Method on the mean improvement score for this population model of students

Ha: There is no interaction effect between Homework Method and Presentation Method on the mean improvement score for this population model of students

2. Ho: There is no interaction effect between Homework Method and Presentation Method on the mean improvement score for this population model of students

Ha: There is an interaction effect between Homework Method and Presentation Method on the mean improvement score for this population model of students

3. Ho: There is no difference in mean improvement score between Homework Method and Presentation Method for this population model of students

Ha: There is a difference in mean improvement score between Homework Method and Presentation Method for this population model of students

4. Ho: There is a difference in mean improvement score between Homework Method and Presentation Method for this population model of students

Ha: There is no difference in mean improvement score between Homework Method and Presentation Method for this population model of students

d. State the value of the test statistic and p-value from the output.

e.Briefly assess the significance of the evidence..

f. State your conclusion in the context of the problem.

Interaction Plot for IMPROVE Data Means 3.0 ASSIST CHECK FULL NO 2.5 Mean 2.0 1.5 1.0- In Person Online TypeANOVA: IMPROVE versus ASSIST, TYPE Factor Information Factor Type Levels Values ASSIST Fixed 3 CHECK, FULL, NO TYPE Fixed 2 In Person, Online Analysis of Variance for IMPROVE Source DF SS MS F P ASSIST 2 8,467 4.233 0.60 0.549 TYPE 1 1.111 1.111 0.16 0.692 ASSIST*TYPE 2 25.756 12.878 1.84 0.166 Error 84 589.067 7.013 Total 89 624.400 Model Summary 5 R-sq R-sq[adj) 2.64815 5.665 0.04% Residual Plots for IMPROVE Normal Probability Plot Versus Fits 99.9 99 06 Percent 50 Residual ......+ 10 5 10 1.5 210 2.5 310 Residual Fitted Value Histogram Versus Order 10 Residual Frequency 0 10 20 30 40 50 60 TO 90 Residual Observation Order