condition mean min max ZT0-3 5.169656666666667 2.83867 6.38228 ZT4-7 2.700915 2.700915 2.700915 ZT8-11 3.47384 3.47384 3.47384 ZT12-15 6.57168 4.50417 8.63919 ZT16-19 8.103455 8.103455 8.103455 ZT20-23 10.54466 10.54466 10.54466