condition mean min max ZT0-3 11.25 11.25 11.25 ZT4-7 2.6 2.6 2.6 ZT8-11 16.45 16.45 16.45 ZT12-15 3.6999999999999997 3.6999999999999997 3.6999999999999997 ZT16-19 54.849999999999994 54.849999999999994 54.849999999999994 ZT20-23 6.45 6.45 6.45