condition mean min max ZT0-3 19.98164902 19.00377344 20.9595246 ZT4-7 9.6611553755 9.235146228 10.087164523 ZT8-11 7.7092681035 7.3207942495000005 8.0977419575 ZT12-15 9.334130997750002 8.8134787195 9.854783276000001 ZT16-19 12.266437739 10.921440738000001 13.61143474 ZT20-23 18.674750547499997 16.713313505 20.63618759