condition mean min max ZT0-3 6.57424 6.57424 6.57424 ZT4-7 3.83235 3.83235 3.83235 ZT8-11 4.041575 4.041575 4.041575 ZT12-15 5.43611 5.43611 5.43611 ZT16-19 9.93146 9.93146 9.93146 ZT20-23 7.35511 7.35511 7.35511