condition mean min max ZT0-3 4.993065 4.7300699999999996 5.25606 ZT4-7 5.73111 5.73111 5.73111 ZT8-11 6.940855 6.940855 6.940855 ZT12-15 0 0 0 ZT16-19 7.56942 7.56942 7.56942 ZT20-23 6.6236049999999995 6.6236049999999995 6.6236049999999995