condition mean min max ZT0-3 25.491116666666667 17.19845 30.45275 ZT4-7 17.94095 17.94095 17.94095 ZT8-11 12.663499999999999 12.663499999999999 12.663499999999999 ZT12-15 14.814625 14.03855 15.590699999999998 ZT16-19 16.641150000000003 16.641150000000003 16.641150000000003 ZT20-23 30.91045 30.91045 30.91045