condition mean min max ZT0-3 15.216616666666667 14.96075 15.4132 ZT4-7 13.471499999999999 13.471499999999999 13.471499999999999 ZT8-11 11.2958 11.2958 11.2958 ZT12-15 13.385575000000001 12.473700000000001 14.297450000000001 ZT16-19 15.9077 15.9077 15.9077 ZT20-23 16.3902 16.3902 16.3902