condition mean min max ZT0-3 3.096005 2.8806149999999997 3.311395 ZT4-7 1.319309 1.319309 1.319309 ZT8-11 1.19347 1.19347 1.19347 ZT12-15 0 0 0 ZT16-19 4.210095 4.210095 4.210095 ZT20-23 3.403345 3.403345 3.403345