condition mean min max ZT0-3 0.884143 0.7076135 0.999225 ZT4-7 0.56405 0.56405 0.56405 ZT8-11 0.228449 0.228449 0.228449 ZT12-15 1.6690174999999998 1.39407 1.943965 ZT16-19 2.77445 2.77445 2.77445 ZT20-23 4.9340850000000005 4.9340850000000005 4.9340850000000005