condition mean min max ZT0-3 371.069289 371.069289 371.069289 ZT4-7 654.7237585 654.7237585 654.7237585 ZT8-11 508.30048150000005 508.30048150000005 508.30048150000005 ZT12-15 387.770443 387.770443 387.770443 ZT16-19 316.22898150000003 316.22898150000003 316.22898150000003 ZT20-23 345.7337745 345.7337745 345.7337745