Question

An office manager is interested in the effect anxiety has on the ability of individuals to learn new material. She is also interested in whether the effect of anxiety depends on the difficulty of new material. An experiment is conducted with the design shown below. 45 participants participated in the study (5 per group). Each subject is given 30 minutes to learn the material, after which the subjects are tested to determine the amount learned. Results are shown below (values represent cell means).

	Anxiety
Difficulty of Material	Low	Medium	High
Low	17.8	17.4	17.6
Medium	15.8	16.4	14.8
High	9	12.6	7.4

The researcher performs a 3 x 3 ANOVA and finds the following results:

Source	SS	df	MS	Fobt	Fcrit
Difficulty	506.844	2	253.422	92.35	3.26
Anxiety	36.844	2	18.442	6.72	3.26
Difficulty x Anxiety	40.756	4	10.189	3.71	2.63
Within	98.80	36	2.744
Total	683.244	44

1. What is the strength of the relationship (eta-square) between the main effects and the dependent variable, and the strength of the relationship between the interaction effect and the dependent variable?

difficulty = Answer; anxiety = Answer; difficulty by anxiety = Answer

2. What is the power of the study for the interaction effect (f) at a = 0.05 (Round off to nearest values in the table}?

Effect	Effect Size	n to enter table	U	Power
Interaction	Answer	Answer	Answer	Answer

Answer 1

1.

Effect	SSEffect	SSTotal	h2
Difficulty	506.844	683.244	0.7418
Anxiety	36.844	683.244	0.0539
Difficulty * Anxiety	40.756	683.244	0.0597

The strength of relationship with difficulty is 74%, with anxiety is 5% and with the interaction effect(difficulty by anxiety) is 6%.