condition mean min max ZT0-3 0.340926 0.340926 0.340926 ZT4-7 0.140562 0.140562 0.140562 ZT8-11 0.019217599999999998 0.019217599999999998 0.019217599999999998 ZT12-15 0.0319378 0.0319378 0.0319378 ZT16-19 0.023547066666666668 0.023547066666666668 0.023547066666666668 ZT20-23 0.114251 0.114251 0.114251