condition mean min max ZT0-3 18.870447 18.870447 18.870447 ZT4-7 27.092855 27.092855 27.092855 ZT8-11 36.9478325 36.9478325 36.9478325 ZT12-15 49.1862165 49.1862165 49.1862165 ZT16-19 31.2142555 31.2142555 31.2142555 ZT20-23 20.703143 20.703143 20.703143