General instructions. This assignment is to be done in your lab session. Submit your assignment from the lab computer during lab time. If the assignment involves SPSS, be sure that when you open SPSS, you set it so that commands are displayed in the output: Edit -> Options, Viewer tab, check box Display commands in the log.
Open a blank Word document for writing your answers to the following questions. At the top of the document type your full name and computer username.
1A. Get the Excel spreadsheet for
Table 14.4. In the spreadsheet, the angle coefficients
should be
-1 0 1 -1 0 1 and 1 -2 1 1 -2 1.
Make a note of the F values for the Angle Main effect, the
Noise main effect, and the Angle x Noise interaction.
1B. Now change the angle coefficients to
-1 1 0 -1 1 0 and 0 -1 1 0 -1 1.
State an intuitive meaning for these coefficients. Make a note of
the F values for the Angle Main effect, the Noise main effect, and the
Angle x Noise interaction. Have they changed relative to the original
set of coefficents?
1C. Now change the angle coefficients to
-1 1 0 -1 1 0 and -1 0 1 -1 0 1.
State an intuitive meaning for these coefficients. Make a note of
the F values for the Angle Main effect, the Noise main effect, and the
Angle x Noise interaction. Have they changed relative to the original
set of coefficents?
1D. Now change the angle coefficients to
-1 1 0 -1 1 0 and 1 -1 0 1 -1 0.
State an intuitive meaning for these coefficients. Make a note of
the F values for the Angle Main effect, the Noise main effect, and the
Angle x Noise interaction. Have they changed relative to the original
set of coefficents? Why?
2A-D. Get the Excel spreadsheet for Table 14.10. Answer all the above questions for it. That is, change the angle coefficients and report what happens to the F ratios.
PURPOSE: A goal of exercises 1 and 2 above is to have you think about how the difference scores used in multivariate analyses can be interpreted as comparisons, and how the F ratio combines the unique contributions of the difference scores. A secondary goal is for you to have the opportunity to use Excel files that explicitly compute all the squared errors and so on that the book talks about.
3. Get the SPSS spreadsheet
for Ch. 14 Table 4. Conduct a complex interaction comparison that
tests whether there is an interaction of noise with upright
vs. non-upright angles. That is, consider upright (angle 0) versus
non-upright (the average of angle 4 and angle 8). Does the difference
between upright and non-upright depend on the presence of noise?
HINT: Use a compute statement to compute an appropriate
interaction contrast for each subject, then do a one-group
t-test.
WHAT TO TURN IN: When you executed the Compute command in
SPSS, it should have logged the syntax in your output. Copy and paste
that Compute command syntax into your Word file. Also copy and paste
the output of the t-test to your word file. Finally, state in an
additional sentence what the degrees of freedom are.
4. Get the SPSS
spreadsheet for Ch. 14 Table 10. Conduct a complex interaction
comparison that tests whether there is an interaction of age with
upright vs. non-upright angles. That is, consider upright (angle 0)
versus non-upright (the average of angle 4 and angle 8). Does the
difference between upright and non-upright depend on the age of the
subjects?
HINT: Use a compute statement to compute an appropriate
interaction contrast for each subject, then do a two-group
t-test.
WHAT TO TURN IN: When you executed the Compute command in
SPSS, it should have logged the syntax in your output. Copy and paste
that Compute command syntax into your Word file. Also copy and paste
the output of the t-test to your word file. Finally, state in an
additional sentence what the degrees of freedom are.
PURPOSE: A goal of exercises 3 and 4 above is to have you think about how a meaningful comparison gets implemented as a specific mathematical difference in the data, for two different designs.
Submit your Word document to the Oncourse Assingment for this week. (Save a copy for your own records.)