condition mean min max ZT0-3 14.553601666666667 6.1727050000000006 20.091900000000003 ZT4-7 5.613745 5.613745 5.613745 ZT8-11 6.135875 6.135875 6.135875 ZT12-15 13.355525 11.19205 15.518999999999998 ZT16-19 17.056350000000002 17.056350000000002 17.056350000000002 ZT20-23 21.649250000000002 21.649250000000002 21.649250000000002