condition mean min max ZT0-3 16.884025 14.673649999999999 19.0944 ZT4-7 7.882565 7.882565 7.882565 ZT8-11 11.61815 11.61815 11.61815 ZT12-15 0 0 0 ZT16-19 23.53365 23.53365 23.53365 ZT20-23 24.4373 24.4373 24.4373