STAT 599 Spring 2013 Homework 3
--------------------------------


1.  Do problem 3(a) given on page 113 of the book.

NOTE:  You have to specify 'weights=y' as one of the arguments of the
'polr' function, since the data are given as *grouped* here.

2.  Do problem 4 given on page 113 of the book.

NOTE:  You have to specify 'weights=Freq' as one of the arguments of the
'multinom' function, since the data are given as *grouped* here.

3.  Do problem 4 given on page 151 of the book.  [Hint:  You could 
    consider converting the happiness variable into a proportion.]

4.  Do problem 6 on page 152 of the book.
 
NOTE:  Examine all relevant aspects of model building that we have 
discussed in class, such a goodness-of-fit, model diagnostics, etc.
For each problem, write a couple of paragraphs summarizing your model and 
your validation of it.

*** For these problems, you will have to load the 
'faraway' package in R to access the data sets.  If you have never
installed it, type
install.packages("faraway")
and follow the directions.

To load the package (and the MASS and nnet packages) for use in an R session, type
library(faraway); library(MASS); library(nnet)

Then you can type
help(uncviet)
and
help(pneumo)
and 
help(happy)
and
help(fruitfly)

for details on these data sets.