Table 1 describes a data set taken from a survey of students sampled over three semesters - spring and fall 1993 and spring 1994 - taking a Principles of Economics course at a medium-sized public college in North Carolina, United States. These data were analyzed using a linear regression model that explored the relationship between lecture attendance and student learning. The results are reported in Table 2.

Table 1: Data for testing the theory that lecture attendance affects grade

Variable Description Mean

grade Student course grade (%) 72.234

skip12 1 if 1 or 2 absences; 0 otherwise 0.277

skip34 1 if 3 or 4 absences; 0 otherwise 0.159

skip56 1 if 5 or 6 absences; 0 otherwise 0.162

skip78 1 if 7 or 8 absences; 0 otherwise 0.061

skip9+ 1if 9 or more absences; 0 otherwise 0.104

SATmath Pre university standardised maths test 515.647

SATverbal Pre university standardised verbal reasoning test 466.96

GPA mean Grade Point Average to date x 100 269.538

colprep 1 is high school program was college prep; 0 otherwise 0.538

HSecon 1 if had high economics, 0 otherwise 0.454

calculus 1 if have take college calculus, 0 otherwise 0.532

econ 1 if previously had a college economics course,

0 otherwise 0.419

hoursstudy Hours of economics studied per week 2.4

hourswork Hours worked per week in a job 7.818

credithours Hours of courses taken for credit that semester 13.081

extracurr 1 if 1 or more extracurricular activities, 0 otherwise 0.72

fratsor 1 if fraternity or sorority member, 0 otherwise 0.214

parents 0 if either parent had a high school education or less;

1 if either went to university;

2 if either gained a university degree;

3 if either studied at...