condition mean min max ZT0-3 20.26271688 17.71295641 22.81247735 ZT4-7 31.426268265 25.57995924 37.27257729 ZT8-11 50.36479992833333 48.39797982 52.33162003666666 ZT12-15 67.55529879 65.30852493666667 69.80207264333333 ZT16-19 63.80221018666667 53.57735526 74.02706511333334 ZT20-23 49.949993525 48.97225516 50.92773189