Question

Application Exercise:
In a study of memory process, rats were first presented with a fear-inducing stimulus on a learning task as soon as they stepped across a line in a test chamber. Afterwards, the rats were divided and given electrical stimulation either 50 or 150 milliseconds after crossing the line. In addition, the rats differed in terms of the area in which the stimulation electrodes were implanted in their brains (Neutral Area, Area A, or Area B). Researchers were interested in the time it took the animals to re-cross the line on a subsequent learning task. The idea is that stimulation of certain areas in the brain would interfere with memory and hence delay learning to avoid the line on the subsequent learning task. The data on time to re-cross the line are below. What can be concluded with ? = 0.05?

                     Area

Time	neutral	A	B
50	26 31 29 41 21	12 19 25 16 15	24 31 19 29 24
150	26 29 24 18 33	26 31 38 38 24	27 20 29 29 22

a) What is the appropriate test statistic?
---Select--- na one-way ANOVA within-subjects ANOVA two-way ANOVA

b) Compute the appropriate test statistic(s) to make a decision about H₀.
Time: critical value =  ; test statistic =  
Decision:  ---Select--- Reject H0 Fail OR to reject H0

Area: critical value =  ; test statistic =  
Decision:  ---Select--- Reject H0 OR Fail to reject H0

Interaction: critical value =  ; test statistic =  
Decision:  ---Select--- Reject H0 OR Fail to reject H0


c) Compute the corresponding effect size(s) and indicate magnitude(s).
Time: ?² = ;  ---Select--- na, trivial effect, small effect, medium effect, large effect
Area: ?² = ;  ---Select--- na, trivial effect, small effect, medium effect, large effect
Interaction: ?² = ;  ---Select--- na, trivial effect, small effect, medium effect, large effect


d) Make an interpretation based on the results.

-There is a time difference in the time it took to step across the line OR.There is no time difference in the time it took to step across the line.    

-There is an area difference in the time it took to step across the line OR .There is no area difference in the time it took to step across the line.    

-There is a time by area interaction in the time it took to step across the line OR There is no time by area interaction in the time it took to step across the line.    

Answer 1

Two-way ANOVA Table

a)Two-way ANOVA

b)(i)Time:Critical value:4.26 , Test statistic:2.8 , Decision:Fail to reject Ho

(ii) Area: Critical value:3.4 , Test statitistic:0.95 , Decision:Fail to reject Ho

(iii)Interaction:Critical value:4.26 , Test statitistic:6.72 , Decision:Reject Ho

c)(i)Time:, large effect

(ii)Area: medium effect

(iii)Interaction: large effect

d)There is a time by area interaction in the time it took to step across the line OR There is no time by area interaction in the time it took to step across the line.