condition mean min max ZT0-3 17.8848898925 15.430787595 20.33899219 ZT4-7 8.46572844975 7.906436810500001 9.025020089 ZT8-11 7.965584478000001 7.833450795500001 8.097718160500001 ZT12-15 7.868043034749999 7.1953791365 8.540706933 ZT16-19 10.67995281975 8.38106381 12.978841829499999 ZT20-23 25.8214939625 21.2692769 30.373711025