condition mean min max ZT0-3 10.636695 8.08094 13.192450000000001 ZT4-7 22.7939 22.7939 22.7939 ZT8-11 31.33515 31.33515 31.33515 ZT12-15 0 0 0 ZT16-19 20.27075 20.27075 20.27075 ZT20-23 14.70665 14.70665 14.70665