condition mean min max ZT0-3 1.7136833333333334 1.1442350000000001 2.71292 ZT4-7 3.42772 3.42772 3.42772 ZT8-11 2.53453 2.53453 2.53453 ZT12-15 4.3174975 3.316095 5.318899999999999 ZT16-19 3.03313 3.03313 3.03313 ZT20-23 1.871525 1.871525 1.871525