condition mean min max ZT0-3 7.8082275 6.8474900000000005 8.768965 ZT4-7 9.499245 9.499245 9.499245 ZT8-11 10.889285000000001 10.889285000000001 10.889285000000001 ZT12-15 0 0 0 ZT16-19 11.789950000000001 11.789950000000001 11.789950000000001 ZT20-23 8.962185 8.962185 8.962185