condition mean min max ZT0-3 16.760374 16.760374 16.760374 ZT4-7 15.143325999999998 15.143325999999998 15.143325999999998 ZT8-11 18.419923 18.419923 18.419923 ZT12-15 13.9280055 13.9280055 13.9280055 ZT16-19 16.5349435 16.5349435 16.5349435 ZT20-23 17.804942 17.804942 17.804942