condition mean min max ZT0-3 11.2223475 10.792745 11.65195 ZT4-7 7.813445 7.813445 7.813445 ZT8-11 8.674479999999999 8.674479999999999 8.674479999999999 ZT12-15 0 0 0 ZT16-19 7.8790949999999995 7.8790949999999995 7.8790949999999995 ZT20-23 7.0676000000000005 7.0676000000000005 7.0676000000000005