A physical therapist tests the reliability of the active knee extension test for hamstring flexibility (degrees). She administers the active knee extension test to 20 subjects on three separate days. The following table contains the resulting data.

Day 1 Day 2 Day 3 50 47 55 24 22 27 37 40 40 24 25 22 45 43 41 25 24 21 37 33 39 30 29 27 39 37 38 30 26 25 20 24 20 32 28 33 33 29 30 44 41 41 34 33 33 35 32 36 33 36 30 38 40 40 45 36 47 52 46