condition mean min max ZT0-3 5.4939025 5.219735 5.76807 ZT4-7 4.16709 4.16709 4.16709 ZT8-11 6.750745 6.750745 6.750745 ZT12-15 0 0 0 ZT16-19 6.861689999999999 6.861689999999999 6.861689999999999 ZT20-23 6.539165000000001 6.539165000000001 6.539165000000001