Mathematics Homework Assignment | Buy Assignments Online
Homework Assignment #4 (10 points)
ANOVA
IMPORTANT: Please hand in to the PSYS 054 dropbox by 3pm on Friday, April 26
Imagine that you are a cognitive scientist interested in differences in visual memory for emotional 
(versus neutral) events. To explore this research area, you set up an experiment in which participants are presented with one of four sets of 30 pictures from the International Affective Picture System (IAPS), a standardized set of images used in psychological research. Participants (N = 24) are randomized to one of four experimental conditions: they view pictures previously reliably coded as either (1) happy, (2) sad, (3) scary, or (4) neutral in emotional tone. After a short delay, participants are asked to recall (write down) descriptions of as many of the pictures as they can remember.
The researchers hypothesize that the groups will differ in the number of pictures remembered.
The data (number of pictures remembered) are below:
Happy
Sad
Scary
Neutral
21
24
24
19
25
25
26
22
28
19
22
15
27
21
27
20
26
15
27
18
27
18
21
16
Assignment:
1. Please calculate the F statistic for a one-way ANOVA testing the so-called “omnibus null hypothesis” for these data. Please provide the notation for H0 in this case as part of your answer and include all calculation details for all steps (6 points).
2. Using Appendix/Table E.3 (available from your textbook or from lecture slides), find the appropriate critical F value for this test; please provide details on how you are obtaining all necessary degrees of freedom (1 point).
3. Comparing your calculated value to the critical value, should the researchers reject or retain the null hypothesis? What does this imply, if anything, about the research question? (1 point).
4. Imagine you are asked to conduct a Bonferonni post-hoc test procedure with these data (do not actually conduct the procedure!) Please describe how you would set up this procedure, specifying what test(s) would be done, how many tests, and what alpha level would be used (2 points). What information would this procedure provide?
