condition mean min max ZT0-3 13.823599999999999 13.5663 14.0809 ZT4-7 12.29445 12.29445 12.29445 ZT8-11 19.10615 19.10615 19.10615 ZT12-15 0 0 0 ZT16-19 20.521050000000002 20.521050000000002 20.521050000000002 ZT20-23 16.81195 16.81195 16.81195