692 Appendices
Appendix: Data Set
Howell and Huessy (1985) reported on a study of 386 children who had, and had not, exhib-
ited symptoms of attention deficit disorder (ADD)—previously known as hyperkinesis or
minimal brain dysfunction—during childhood. In 1965, teachers of all second-grade school
children in a number of schools in northwestern Vermont were asked to complete a ques-
tionnaire for each of their students dealing with behaviors commonly associated with ADD.
Questionnaires on these same children were again completed when the children were in the
fourth and fifth grades and, for purposes of this data set only, those three scores were aver-
aged to produce a score labeled ADDSC. The higher the score, the more ADD-like behaviors
the child exhibited. At the end of ninth grade and again at the end of twelfth grade, informa-
tion on the performances of these children was obtained from school records. These data
offer the opportunity to examine questions about whether later behavior can be predicted
from earlier behavior and to examine academically related variables and their interrelation-
ships. The data are referred to in many of the exercises at the end of each chapter. A descrip-
tion of each variable follows.
ADDSC Average of the three ADD-like behavior scores obtained in
elementary school
GENDER 15 male; 2 5 female
REPEAT 15 repeated at least one grade; 0 5 did not repeat a grade
IQ IQ obtained from a group-administered IQ test
ENGL Level of English in ninth grade: 1 5 college prep; 2 5 general;
35 remedial
ENGG Grade in English in ninth grade: 4 5 A; 3 5 B; and so on
GPA Grade point average in ninth grade
SOCPROB Social problems in ninth grade: 1 5 yes; 0 5 no
DROPOUT 15 dropped out before completing high school; 0 5 did not
drop outAppendix: Computer Data Sets
The website (www.uvm.edu/~dhowell/methods/) contains many data sets. The data sets rep-
resent a combination of data from actual studies, data that have been created to mimic the data
from actual studies, data from all examples and exercises at the end of each chapter. It also
contains two sets of random numbers that have been generated to illustrate certain points.
All of these data sets are standard ASCII files, meaning that they can be read by virtually all
computer programs and can be edited if necessary with standard editors available on any com-
puter system (for example, Microsoft Wordpad). In addition, they can be edited by any word
processor that can produce an ASCII file (sometimes referred to as a text file or a DOS file).
The following, unusually complex, data sets are the focus of a number of homework
exercises in many different chapters. The descriptions that follow are intended to explain the
study from which the data were drawn and to describe how the data are arranged in the data
set. You should refer to these descriptions when working with these data sets. The data sets
drawn directly from tables and exercises are much simpler, and their structure can be inferred
from the text.
In addition, this Web site contains copies of data from most of the examples and exercises
in the book. Those data sets are described in a file on the Web site, and will not be described
further here.Add.dat
The data in this file come from a study by Howell and Huessy (1985). The data are described
above.