condition mean min max ZT0-3 8.53995 8.53995 8.53995 ZT4-7 6.53734 6.53734 6.53734 ZT8-11 6.144545 6.144545 6.144545 ZT12-15 6.60416 6.60416 6.60416 ZT16-19 8.44725 8.44725 8.44725 ZT20-23 10.22515 10.22515 10.22515