condition mean min max ZT0-3 17.153755 14.158615 20.24555 ZT4-7 18.97285 18.97285 18.97285 ZT8-11 19.437079999999998 19.437079999999998 19.437079999999998 ZT12-15 15.0313825 13.433565 16.6292 ZT16-19 19.6162 19.6162 19.6162 ZT20-23 26.58625 26.58625 26.58625