condition mean min max ZT0-3 5.19834 5.19834 5.19834 ZT4-7 3.07789 3.07789 3.07789 ZT8-11 6.016475 6.016475 6.016475 ZT12-15 9.41481 9.41481 9.41481 ZT16-19 9.42172 9.42172 9.42172 ZT20-23 7.65058 7.65058 7.65058