condition mean min max ZT0-3 2.801858333333333 1.653705 3.574515 ZT4-7 1.58629 1.58629 1.58629 ZT8-11 2.260085 2.260085 2.260085 ZT12-15 4.0339425 3.889925 4.177960000000001 ZT16-19 4.0559899999999995 4.0559899999999995 4.0559899999999995 ZT20-23 5.197545 5.197545 5.197545