condition mean min max ZT0-3 38.025283333333334 35.78635 39.89295 ZT4-7 28.58655 28.58655 28.58655 ZT8-11 24.067749999999997 24.067749999999997 24.067749999999997 ZT12-15 29.9866 29.03725 30.93595 ZT16-19 31.557049999999997 31.557049999999997 31.557049999999997 ZT20-23 39.83435 39.83435 39.83435