Pre-Post Data Example MTB > describe c1-c2 N MEAN MEDIAN TRMEAN STDEV SEMEAN C1 20 25.80 27.00 26.28 6.30 1.41 C2 20 28.30 27.50 28.61 5.95 1.33 MIN MAX Q1 Q3 C1 10.00 33.00 22.25 31.00 C2 15.00 36.00 26.00 33.75 MTB > let c3 = c2 - c1 MTB > describe c3 N MEAN MEDIAN TRMEAN STDEV SEMEAN C3 20 2.500 3.000 2.778 2.893 0.647 MIN MAX Q1 Q3 C3 -6.000 6.000 1.000 5.250 MTB > stem c3 Stem-and-leaf of C3 N = 20 Leaf Unit = 1.0 1 -0 6 1 -0 1 -0 2 -0 0 6 0 0011 (9) 0 222333333 5 0 5 0 66666 MTB > boxplot c3 --------------- * ----I + I------ --------------- --------+---------+---------+---------+---------+--------C3 -5.0 -2.5 0.0 2.5 5.0 MTB > tinterval 90 c3 N MEAN STDEV SE MEAN 90.0 PERCENT C.I. C3 20 2.500 2.893 0.647 ( 1.381, 3.619) MTB > MTB > tinterval 99 c3 N MEAN STDEV SE MEAN 99.0 PERCENT C.I. C3 20 2.500 2.893 0.647 ( 0.649, 4.351)