condition mean min max ZT0-3 1.9259856666666666 0.993717 2.99906 ZT4-7 2.01503 2.01503 2.01503 ZT8-11 0.9871415000000001 0.9871415000000001 0.9871415000000001 ZT12-15 2.070855 1.55715 2.58456 ZT16-19 2.02369 2.02369 2.02369 ZT20-23 1.825485 1.825485 1.825485