condition mean min max ZT0-3 14.548964 14.548964 14.548964 ZT4-7 18.452392 18.452392 18.452392 ZT8-11 19.6109045 19.6109045 19.6109045 ZT12-15 19.272239499999998 19.272239499999998 19.272239499999998 ZT16-19 19.227506499999997 19.227506499999997 19.227506499999997 ZT20-23 18.815481 18.815481 18.815481