Gulanick ({Heart and Lung, 1991) studied patients who were
recovering from heart surgery.  She was interested in whether different
combinations of supervised exercise or teaching would affect
patients' self-efficacy (or confidence) to perform physical
activity.

Patients were randomly assigned to one of three groups.  Group
1 received teaching, treadmill exercise testing, and exercise training
three times per week.  Group 2 received only teaching and exercise
testing.  Group 3 received only routine care without supervised exercise
or teaching.  After 4 weeks, each patient was scored on self-efficacy.

Self-efficacy was measured on a continuous scale and scores were assumed
to be distributed normally in each of the populations of interest.

The variables in the dataset are:
    score
    group

Data is taken from Daniel, WW (1999) Biostatistics:  A Foundation for
Analysisin the Health Sciences.  Wiley.