condition mean min max ZT0-3 12.71740809 9.574123515 15.860692665 ZT4-7 18.3549748575 16.20284332 20.507106395 ZT8-11 16.181815937499998 15.522617949999999 16.841013925 ZT12-15 15.719345685 14.396336690000002 17.04235468 ZT16-19 23.7396213375 20.04994234 27.429300335 ZT20-23 43.406025187500006 39.41835735 47.393693025000005