condition mean min max ZT0-3 11.2844525 10.420705 12.1482 ZT4-7 11.98435 11.98435 11.98435 ZT8-11 7.305070000000001 7.305070000000001 7.305070000000001 ZT12-15 0 0 0 ZT16-19 6.276624999999999 6.276624999999999 6.276624999999999 ZT20-23 8.424395 8.424395 8.424395