BSAD 6312 Regression Assignment 8
1. For the condo data set output handout in class on September 16 where Selling Price is
regressed against Age and Square Footage, evaluate the validity of the LINE
assumptions.
2. For the data of problem 7.12 in your book (with output posted on our class web page)
answer the following questions:
a. Identify any outliers from the model, i.e. observations of unexpectedly large
residuals? Justify your conclusion.
b. Are there any outliers in the X space, .i.e. observations unexpectedly far from the
xbar vector? Justify your conclusion.
c. Do any of the above observations exert undue influence on the estimated ’s or
the predicted Yhats? Why or why not?
3. For your individual model and data sets of Assignment 3 with your own software output,
answer the following questions:
a. Evaluate the validity of the LINE assumptions
b. Identify any outliers from the model, i.e. observations of unexpectedly large
residuals? Justify your conclusion.
c. Are there any outliers in the X space, .i.e. observations unexpectedly far from the
xbar vector? Justify your conclusion.
d. Do any of the above observations exert undue influence on the estimated ’s or
the predicted Yhats? Why or why not?
4. For your model and data set, do scatterplots suggest transformations of X (to correct
nonlinearity) or Y (to correct nonnormality or unequal variance)? If so, do these
transformations remedy the violation of the assumption?