condition mean min max ZT0-3 17.341383333333333 11.88575 20.41675 ZT4-7 9.919385 9.919385 9.919385 ZT8-11 10.810179999999999 10.810179999999999 10.810179999999999 ZT12-15 8.740461425 7.52324785 9.957675 ZT16-19 5.132894 5.132894 5.132894 ZT20-23 18.29435 18.29435 18.29435