condition mean min max ZT0-3 29.15 29.15 29.15 ZT4-7 7.5 7.5 7.5 ZT8-11 21.25 21.25 21.25 ZT12-15 20.950000000000003 20.950000000000003 20.950000000000003 ZT16-19 41.349999999999994 41.349999999999994 41.349999999999994 ZT20-23 76.65 76.65 76.65