condition mean min max ZT0-3 12.139675 11.546199999999999 12.73315 ZT4-7 8.06302 8.06302 8.06302 ZT8-11 4.46312 4.46312 4.46312 ZT12-15 0 0 0 ZT16-19 9.48585 9.48585 9.48585 ZT20-23 9.453405 9.453405 9.453405