condition mean min max ZT0-3 218.354909 218.354909 218.354909 ZT4-7 329.373375 329.373375 329.373375 ZT8-11 348.651473 348.651473 348.651473 ZT12-15 320.570382 320.570382 320.570382 ZT16-19 225.794545 225.794545 225.794545 ZT20-23 207.6695675 207.6695675 207.6695675