CPSY 501 Fall 2010 HW Assignment #2:
Multiple Regression
Total: 20 marks. Due: Fri 29 Oct 09:00am, uploaded to myCourses
Dataset
Please download from the course website (under "assignments") and use the
HW2-Klassen_SWB.sav dataset for this assignment.
This dataset is from Derrick Klassen's thesis on spiritual well-being of
university students. The data are from self-reports of 160 people at TWU
(mostly undergraduate students, but also some graduate students).
The outcome variable is spiritual well-being (SWB).
Various predictor variables include
- degree of Quest religious orientation (Quest),
- level on Personal Meaning Profile (PMP),
- strength of Moratorium Identity Status assessed in the Belief domain (MIS-Belief), and
- strength of Moratorium Identity Status assessed in the Relationships domain (MIS-Rel).
Based on existing theory of psychology of religion, the predictors can be grouped
into 3 blocks: (1) Quest, (2) Personal Meaning, and (3) both developmental
(Moratorium) variables. You will need to run hierarchical regression tests
in SPSS to answer the following questions.
Questions
-
Outliers (2 marks)
Identify the variable(s) with potential univariate outliers, and for each of those
variables report which cases have potentially outlying values.
-
Parametricity (3 marks)
Does the outcome variable (Spiritual Well Being, SWB) appear to meet the
assumptions of parametricity? Identify each assumption, and describe how you
checked for each assumption.
In a real study, you would remove the outliers and make changes to accommodate for
violations of parametricity. For purposes of this assignment, however, do
not alter the dataset -- for the rest of this assignment, you may assume
that the data meet the assumptions for regression.
-
Total Effect of Model (1 mark)
In a broader population of young adults in university, what percentage of the
total variance in SWB can be accounted for by Quest, Personal Meaning, and
Moratorium Status?
-
Direction of Quest Effect (2 marks)
Identify the direction of the relationship between Quest and SWB.
Is it
- positive (i.e., as one goes up, the other goes up),
- negative (as one goes up, the other goes down), or
- negligible (there is not significant relationship)?
Explain how you reached your conclusion and report the appropriate numbers to
support your answer.
-
Unique Effect of Moratorium (1 marks)
How much extra variation in participants’ SWB levels did the developmental
variables explain, over and above the effects of Quest and Personal Meaning?
-
Marcia's Developmental Model (3 marks)
In the developmental theories of Marcia, a process of moratorium is often a
distressing period in life that can nevertheless be helpful over the longer
term in the process of identity development. Describe ways that this analysis
fits and/or does not fit with that model.
-
Quest vs. Moratorium (3 marks)
Briefly compare the strength of the zero-order effect and the unique effect of
the Quest orientation in explaining Spiritual Well-Being. Is the unique Quest
effect stronger or weaker than the Moratorium Status effect?
-
Overly Influential Cases (3 marks)
Assess this data set for any potentially “overly influential” cases.
(Do not remove outliers before you conduct your assessment- doing so may change
the data set and, consequently, mess up your response to this question.) (See
textbook and notes for lecture 05.) In a short paragraph, identify the criteria
that you used for determining whether you have an overly influential case.
Identify the case number of the participant with the highest leverage value.
APA Style (2 marks)
Format your answers in a single document (Word .doc or similar), clearly
formatted and written in complete sentences. From this assignment and onward,
you are required to use proper APA manuscript style!
Include relevant figures within your document, following APA style for figures.
Also create a clean SPSS output file (.spv) showing the relevant analyses and
plots. Make sure your SPSS output file doesn't have any output from any other
"trial runs" you did! It is possible to edit an output file to delete extraneous
output.
Turn-in
You should upload to myCourses the following:
- Your write-up as a Word .doc (or similar), in APA style
- Your clean SPSS output file (.spv)