condition mean min max ZT0-3 2.200965 2.200965 2.200965 ZT4-7 1.5783 1.5783 1.5783 ZT8-11 1.7211 1.7211 1.7211 ZT12-15 2.75618 2.75618 2.75618 ZT16-19 5.637475 5.637475 5.637475 ZT20-23 2.8069800000000003 2.8069800000000003 2.8069800000000003