condition mean min max ZT0-3 3.479265 3.479265 3.479265 ZT4-7 2.3074950000000003 2.3074950000000003 2.3074950000000003 ZT8-11 4.28505 4.28505 4.28505 ZT12-15 8.282595 8.282595 8.282595 ZT16-19 9.294885 9.294885 9.294885 ZT20-23 5.92352 5.92352 5.92352