condition mean min max ZT0-3 7.889575 6.526705 8.914285 ZT4-7 8.123014999999999 8.123014999999999 8.123014999999999 ZT8-11 7.51415 7.51415 7.51415 ZT12-15 9.9973025 9.49446 10.500145 ZT16-19 8.419015 8.419015 8.419015 ZT20-23 9.288895 9.288895 9.288895