condition mean min max ZT0-3 6.2162025 5.87003 6.562375 ZT4-7 6.353675 6.353675 6.353675 ZT8-11 8.710665 8.710665 8.710665 ZT12-15 0 0 0 ZT16-19 8.823550000000001 8.823550000000001 8.823550000000001 ZT20-23 8.022185 8.022185 8.022185