condition mean min max ZT0-3 8.811975 7.6444849999999995 9.474720000000001 ZT4-7 6.40654 6.40654 6.40654 ZT8-11 7.618869999999999 7.618869999999999 7.618869999999999 ZT12-15 7.3687475000000004 6.62898 8.108515 ZT16-19 6.979975 6.979975 6.979975 ZT20-23 10.382819999999999 10.382819999999999 10.382819999999999