# Teaching evaluation:
# Three teachers: Jay, Pat and Robin, teaching the same course to
#   three separate classes with 6, 14, and 11 students, respectively.
# If all students are identical at the beginning of the class, then
#   we only need to check the final performance. However, if one teacher
#   happens to get good students to start with, then his students will
#   tend to have high grade at the end even if the teacher may not be 
#   good. So performance at the beginning should be taken into consideration.
Teacher	PreS	AftS
JAY	69	75
JAY	69	70
JAY	71	73
JAY	78	82
JAY	79	81
JAY	73	75
PAT	69	70
PAT	68	74
PAT	75	80
PAT	78	85
PAT	68	68
PAT	63	68
PAT	72	74
PAT	63	66
PAT	71	76
PAT	72	78
PAT	71	73
PAT	70	73
PAT	56	59
PAT	77	83
ROBIN	72	79
ROBIN	64	65
ROBIN	74	74
ROBIN	72	75
ROBIN	82	84
ROBIN	69	68
ROBIN	76	76
ROBIN	68	65
ROBIN	78	79
ROBIN	70	71
ROBIN	60	61