Question

1. A researcher is interested in the effects of sleep deprivation and caffeine intake on mood. Participants were randomly assigned to a sleep condition (normal or deprived) and a caffeine condition (0 cups, 2 cups, or 4 cups). After the manipulations, mood was measured (such that higher numbers indicated better mood). The results were as follows:

                   Normal Condition                                      Deprived Condition

         0 cups        2 cups        4 cups                    0 cups        2 cups        4 cups

            16              18              18                          0                5                6

            17              20              17                          6                4                8

            20              20              17                          3                4                6

            19              19              17                          2                2                7

            18              18              16                          4                5                8

NOTE that this is a 3X2 (or could be said “2X3”) two-way analysis of variance. The caffeine factor has three levels (0 cups, 2 cups, or 4 cups).

1. Using SPSS, run a two-way analysis of variance. Based on the results, fill in the chart of the cell and marginal means below.

		Sleep Condition
		Normal	Deprived
Caffeine Condition	0 cups
	2 cups
	4 cups

2. Looking at the marginal means above:

1. Does there appear to be a main effect of Sleep Condition on mood? Why or why not?  

2. Does there appear to be a main effect of Caffeine Condition on mood? Why or Why not?

3. Does there appear to be an interaction between Sleep Condition and Caffeine Condition on mood? Why or why not?

3. Report the results of the two-way analysis of variance in APA style and paste the output (Descriptive statistics table, test of between subjects effects table).

Answer 1

(a)

		Sleep Condition
	Means:
		Normal	Deprived
	0 cups	18.0	3.0	10.5
Caffeine Conditioner	2 cups	19.0	4.0	11.5
	4 cups	17.0	7.0	12.0
		18.0	4.7	11.3

(b) There is no main effect of Caffeine Conditioner.

There is a main effect of Sleep Condition.

There is an interaction effect.

(c) The SPSS output is:

There is no main effect of Caffeine Conditioner. (F(2, 24) = 3.043, p > 0.05)

There is a main effect of Sleep Condition. (F(1, 24) = 695.652, p < 0.05)

There is an interaction effect. (F(2, 24) = 10.870, p < 0.05)