A "subliminal" message is below our threshold of awareness but may
nonetheless influence us.  Can subliminal messages help students learn
math?  A group of students who had failed the mathematics part of the
City University of New York Skills Assessment Test agreed to participate in
a study to find out.

All received a daily subliminal message, flashed on a screen too
rapidly to be consciously read.  The treatment group of 10 students
(chosen at random) was exposed to "Each day I am getting better in math."
The control group of 8 students was exposed to a neutral message, "People
are walking on the street."  All students participated in a summer program
designed to raise their math skills, and all took the assessment test
again at the end of the program.  The dataset "subliminalmath.dat" gives
data on the subjects' scores before and after the program.  The variables
are:

   group:  T = treatment, C = control
   score before
   score after