Can you help me with this using R please:

subj pre 10 11 12 13 14 15 16 17 18 19 20 47.7 55.3 70.9 53.8 69.6 51.5 48.5 55 53.6 47.5 42.3 60.2 71.7 50.9 61.2 47.7 72.2 cohort post 58.1 41.8 58.8 50.4 62.4 48.9 61.9 48.9 41.5 45.4 49 43.5 38.8 56.8 73.6 55.5 44.7 52.8 42.2 65.2