condition mean min max ZT0-3 13.468513333333334 6.5525400000000005 18.5031 ZT4-7 6.81024 6.81024 6.81024 ZT8-11 10.014759999999999 10.014759999999999 10.014759999999999 ZT12-15 14.15295 13.0321 15.273800000000001 ZT16-19 14.626000000000001 14.626000000000001 14.626000000000001 ZT20-23 21.427500000000002 21.427500000000002 21.427500000000002