Pollard homework 11
Statistics 101-106, Fall 1998
Pollard homework sheet 11
Due: Thursday 3 December
Lecture 11 used information extracted from the April 1990 Consumer
Reports. I borrowed the data set from the Splus statistical
analysis program (the program that I use routinely).
You may work with the data for only the four countries discussed in class, if you wish.
Regress logPrice on the two predictors logHP and German (the indicator
for cars from Germany). Repeat the exercise, with each of the other
country indicators replacing the indicator for Germany in turn.
Why does Minitab not complain about redundant variables in part (i)?
Interpret the output from each of the four regressions from part (i).
- Are there any other variables in the data set that might offer a
better explanation for the apparent Country effect? (You might try
regressions with Type or Reliability included amongst the predictors.)
- Are there any variables in the data set that capture the idea of
a luxury car, or a car that has a good reason for being expensive? (I
fear I know too little about cars to give a good answer to this
- Based on what you can determine from the data, answer the
question: Are German cars really more expensive than comparable cars
from other countries? How confident are you of your answer? Would
your conclusion apply to a comparison between all cars on the market,
or are there any caveats that need to be attached?