condition mean min max ZT0-3 1.8753675 0.8325625 2.43281 ZT4-7 1.3615599999999999 1.3615599999999999 1.3615599999999999 ZT8-11 1.297976 1.297976 1.297976 ZT12-15 1.22022925 0.4619025 1.9785560000000002 ZT16-19 1.011096 1.011096 1.011096 ZT20-23 0.871258 0.871258 0.871258