condition mean min max ZT0-3 2.094185 1.8778899999999998 2.31048 ZT4-7 2.32845 2.32845 2.32845 ZT8-11 3.1449499999999997 3.1449499999999997 3.1449499999999997 ZT12-15 0 0 0 ZT16-19 3.4123650000000003 3.4123650000000003 3.4123650000000003 ZT20-23 3.398575 3.398575 3.398575