condition mean min max ZT0-3 7.986423 7.986423 7.986423 ZT4-7 8.916598 8.916598 8.916598 ZT8-11 11.672360000000001 11.672360000000001 11.672360000000001 ZT12-15 8.754721499999999 8.754721499999999 8.754721499999999 ZT16-19 10.118332500000001 10.118332500000001 10.118332500000001 ZT20-23 8.0830295 8.0830295 8.0830295