condition mean min max ZT0-3 8.451928005 7.651445467 9.252410543 ZT4-7 4.45418689575 4.0185946144999996 4.889779177 ZT8-11 6.118906320000001 5.0830246365 7.1547880035 ZT12-15 8.9490500435 7.347732712 10.550367375 ZT16-19 17.0778945 14.389077605 19.766711395 ZT20-23 28.4481407525 28.363846625 28.532434879999997