condition mean min max ZT0-3 18.428793333333335 9.994330000000001 23.84975 ZT4-7 9.755305 9.755305 9.755305 ZT8-11 12.014334999999999 12.014334999999999 12.014334999999999 ZT12-15 10.6470725 9.130595 12.16355 ZT16-19 18.437199999999997 18.437199999999997 18.437199999999997 ZT20-23 31.76595 31.76595 31.76595