Quiz 6 Psyc 541 Summer 2019 Online25 points

1.(15 points) In a study of postmeningitic and postencephalitic brain damage, each subject was given a battery of tests, providing a composite score for each. Low scores for the composite measure presumably represented a considerable degree of residual brain damage. The subjects were divided into three groups according to type of initial infection and into three crossed groups according to time since apparent physical recovery from the illness. The data are below. Fill in the correct omega squared and cohen F for each source of variance.

1-2 Years3-5 Years7-10 Years

Postencephalitic71.762.2550.00

Postmeningitic82.079.2560.0

Postoperative Control71.7581.7589.75

SSdfMSFomega sqCohen F

Type of Infection2413.55621206.77814.224*

Time536.2222268.1113.16

Type x Time2194.4444548.6116.466*

Error2290.752784.843

*p<.05

What is the average variance within the groups? _______________ (put in a number)

What is the variability of the Type of Infection Means ignoring the effects of time? __ (put in a number)

How many subjects are in each group? _________________

What is the variance of the cell means around the grand mean after the variability due to the main effects has been removed. ___________________

If the variability among the main effect means of Time was no greater than you would expect by chance, what should the F value be for testing the main effect of time.___________________

Complete subsequent Tukey Tests and LSD tests on all significant effects and state your conclusions. When conducting post hoc tests for the type of infection x Time interaction, I want you to examine the effects of type of brain damage at each level of time.

1-2 Years3-5 Years7-10 Years

Postencephalitic71.762.2550.00

Postmeningitic82.079.2560.0

Postoperative Control71.7581.7589.75

Main Effect of Infection

PostencephaliticPostmeningiticPostoperative Control

61.3273.7581.08

Critical difference Tukey =

Critical difference LSD =

Conclusions Tukey:

Conclusions LSD:

Subsequent Tests for Infection x Time Interaction

Critical Difference Tukey =

Critical Difference LSD =

1-2 years

Conclusions: Tukey:

Conclusions: LSD:

3-5 years

Conclusions:Tukey:

Conclusions:LSD:

7-10 years

Conclusions:Tukey:

Conclusions:LSD:

2.(10 points) Describe a main effect, simple effect and an interaction is and what the relationship between simple effects and interactions is?