condition mean min max ZT0-3 20.179669 20.179669 20.179669 ZT4-7 17.991339500000002 17.991339500000002 17.991339500000002 ZT8-11 15.413872000000001 15.413872000000001 15.413872000000001 ZT12-15 16.6145785 16.6145785 16.6145785 ZT16-19 25.711333000000003 25.711333000000003 25.711333000000003 ZT20-23 29.0202345 29.0202345 29.0202345