condition mean min max ZT0-3 11.370751666666667 9.36525 12.39565 ZT4-7 9.261305 9.261305 9.261305 ZT8-11 6.1129299999999995 6.1129299999999995 6.1129299999999995 ZT12-15 8.708555 7.155855000000001 10.261255 ZT16-19 10.004745 10.004745 10.004745 ZT20-23 9.44567 9.44567 9.44567