condition mean min max ZT0-3 3.36483 3.36483 3.36483 ZT4-7 2.31304 2.31304 2.31304 ZT8-11 2.167925 2.167925 2.167925 ZT12-15 2.6712100000000003 2.6712100000000003 2.6712100000000003 ZT16-19 3.98766 3.98766 3.98766 ZT20-23 3.57138 3.57138 3.57138