condition mean min max ZT0-3 386.091466 386.091466 386.091466 ZT4-7 487.709473 487.709473 487.709473 ZT8-11 512.8067725 512.8067725 512.8067725 ZT12-15 470.54787899999997 470.54787899999997 470.54787899999997 ZT16-19 439.9976465 439.9976465 439.9976465 ZT20-23 437.602748 437.602748 437.602748