condition mean min max ZT0-3 9.606185 9.606185 9.606185 ZT4-7 7.973879999999999 7.973879999999999 7.973879999999999 ZT8-11 8.917504999999998 8.917504999999998 8.917504999999998 ZT12-15 8.181925 8.181925 8.181925 ZT16-19 10.29692 10.29692 10.29692 ZT20-23 9.01888 9.01888 9.01888