condition mean min max ZT0-3 246.065991 246.065991 246.065991 ZT4-7 232.3737055 232.3737055 232.3737055 ZT8-11 240.451282 240.451282 240.451282 ZT12-15 264.03974900000003 264.03974900000003 264.03974900000003 ZT16-19 275.9663365 275.9663365 275.9663365 ZT20-23 252.5080775 252.5080775 252.5080775