condition mean min max ZT0-3 17.065078 17.065078 17.065078 ZT4-7 18.2778305 18.2778305 18.2778305 ZT8-11 20.116098 20.116098 20.116098 ZT12-15 16.1331755 16.1331755 16.1331755 ZT16-19 19.372262 19.372262 19.372262 ZT20-23 18.322644 18.322644 18.322644