condition mean min max ZT0-3 8.781105 8.781105 8.781105 ZT4-7 9.591285 9.591285 9.591285 ZT8-11 8.350495500000001 8.350495500000001 8.350495500000001 ZT12-15 8.299330000000001 8.299330000000001 8.299330000000001 ZT16-19 9.384466499999998 9.384466499999998 9.384466499999998 ZT20-23 8.488016 8.488016 8.488016