condition mean min max ZT0-3 17.86535 17.86535 17.86535 ZT4-7 18.94135 18.94135 18.94135 ZT8-11 14.1606 14.1606 14.1606 ZT12-15 16.97035 16.97035 16.97035 ZT16-19 18.86515 18.86515 18.86515 ZT20-23 16.544249999999998 16.544249999999998 16.544249999999998