condition mean min max ZT0-3 1976.75 1976.75 1976.75 ZT4-7 2266.9 2266.9 2266.9 ZT8-11 1889.6999999999998 1889.6999999999998 1889.6999999999998 ZT12-15 1873.35 1873.35 1873.35 ZT16-19 2156.9 2156.9 2156.9 ZT20-23 2156.8500000000004 2156.8500000000004 2156.8500000000004