condition mean min max ZT0-3 1.188151 0.920322 1.4559799999999998 ZT4-7 0.737436 0.737436 0.737436 ZT8-11 1.045083 1.045083 1.045083 ZT12-15 0 0 0 ZT16-19 1.4485649999999999 1.4485649999999999 1.4485649999999999 ZT20-23 1.81893 1.81893 1.81893