condition mean min max ZT0-3 18.70534954 16.33186359 21.07883549 ZT4-7 8.928469431749999 8.781047291 9.0758915725 ZT8-11 10.43944190425 7.982970282 12.895913526500001 ZT12-15 13.974727829999999 12.653780265 15.295675395 ZT16-19 15.4402972575 14.56195213 16.318642385 ZT20-23 18.351272837499998 17.638524335 19.06402134