condition mean min max ZT0-3 0.7359026666666666 0.251293 1.654545 ZT4-7 2.3841 2.3841 2.3841 ZT8-11 1.5603699999999998 1.5603699999999998 1.5603699999999998 ZT12-15 0.8015565 0.361399 1.241714 ZT16-19 0.6322245 0.6322245 0.6322245 ZT20-23 0.1882037 0.1882037 0.1882037