# Chapter 1: Introduction

**1.1.** Have a look at the models (a) and (b) from Example 1.1.

a) As pointed out in Section 3 in Appendix A, one-sided tests are more meaningful than two-sided when testing model parameters. This is one of several good reasons for offering some thoughts on the likely interrelations between the model variables. Do that, and write down your conclusions.

b) Estimate the two models using SPSS. Interpret and compare the results.

You can download the data: bwght.sav

The variables in the data set are:

faminc 1988 family income, $1000s

cigtax cigarette tax in home state, 1988

cigprice cigarette price in home state, 1988

bwght birth weight, ounces

fatheduc father's years of education

motheduc mother's years of education

parity Kbirth order of child

male =1 if male child

white =1 if white

cigs cigarettes smoked per day while pregnant

bwghtlbs birth weight, pounds