condition mean min max ZT0-3 5.11526445025 4.1417856275 6.0887432729999995 ZT4-7 2.7938550715 2.5653095615 3.0224005815 ZT8-11 3.9480612600000002 2.9557088559999998 4.940413664 ZT12-15 6.459274358 5.647183213 7.271365503 ZT16-19 8.479525047500001 7.8044161050000005 9.15463399 ZT20-23 10.9468932435 10.122742567 11.77104392