condition mean min max ZT0-3 28.267088 28.267088 28.267088 ZT4-7 27.113536 27.113536 27.113536 ZT8-11 28.889063999999998 28.889063999999998 28.889063999999998 ZT12-15 37.6601235 37.6601235 37.6601235 ZT16-19 30.699047999999998 30.699047999999998 30.699047999999998 ZT20-23 30.4209805 30.4209805 30.4209805