condition mean min max ZT0-3 2.0359583333333333 1.465455 2.3785600000000002 ZT4-7 1.649895 1.649895 1.649895 ZT8-11 1.6885 1.6885 1.6885 ZT12-15 2.190935 1.9746899999999998 2.4071800000000003 ZT16-19 2.02491 2.02491 2.02491 ZT20-23 2.8434749999999998 2.8434749999999998 2.8434749999999998