condition mean min max ZT0-3 4.524898666666666 1.270586 9.839604999999999 ZT4-7 5.36549 5.36549 5.36549 ZT8-11 2.187335 2.187335 2.187335 ZT12-15 1.8966575 1.6660050000000002 2.12731 ZT16-19 1.76529 1.76529 1.76529 ZT20-23 1.2573699999999999 1.2573699999999999 1.2573699999999999