- A usability engineer would like to develop a model to
predict the usability of a GUI from the organization of GUI
objects (i.e. menus, list boxes, radio buttons etc.). The
engineer uses a widely used index as a measure of
organization of the GUI objects, and time required to
complete a specific set of tasks as the measure of
usability.
The engineer collects data for several GUI designs and
computes the following statistics:
- Usability: Mean=22.3; Standard deviation=31.1
- Index: Mean=612.8; Standard deviation=507.7
If the correlation coefficient is 0.94 and
the simple linear regression model is appropriate.
- State the the regression model.
- Estimate the coefficients of the regression line.
- Interpret your estimates.
-
A DePaul administrator believes that DePaul graduates are offered
better starting salaries than UIC graduates. She compiles a list
of seniors with job offers from both schools and randomly
selects ten from each list to be interviewed.
Assume that these
data represent the starting
salaries in thousands of dollars for the twenty graduates interviewed.
- Would you analyze these data using a paired or two independent sample approach. Justify your answer.
- The administrator is familiar with regression and would like you
to analyze these data using regression. Write the SAS code to do
this. Provide the data step and the procedures in the procedure
step to conduct a thorough analysis.
Note:You do not need to analyze the data but you should make sure that the code works and is complete.
-
You have been asked to analyze a SAS report which
was produced to test the null hypothesis that
a particular testing methodology is equal in effectiveness to
some other testing methodology (say white box vs. black box testing)
against the two sided alternative that they are not equal.
Conduct a thorough analysis using the methods
outlined in Knafl, chapter 4.
Note: Your analysis should include a post
hoc analysis.