A study published in Teaching Psychology (May 1998) examined how external clues influence student performance. Undergraduate students were randomly assigned to one of four different midterm examinations. Form 1 was printed on blue paper and contained difficult questions, while form 2 was also printed on blue paper but contained simple questions. Form 3 was printed on red paper, with difficult questions: form 4 was printed on red paper with simple questions. The researchers were interested in the impact that Color (red or blue) and Question (simple or difficult) had on mean exam score.

a. What experimental design was employed in this study? Identify the factors and treatments.
b. The researchers conducted an ANOVA and found a significant interaction between Color and Question (p-value c. The sample mean scores (percentage correct) for the four exam forms are listed in the table above. Plot the four means on a graph to illustrate the Color × Question interaction.

Form Color Question Mean Score Blue Blue Red Red Difficult Simple Difficult Simple 53.3 80.0 39.3 73.6