condition mean min max ZT0-3 2.440401166 2.264007541 2.6167947910000002 ZT4-7 2.7973873654999997 2.0188724455 3.5759022854999998 ZT8-11 4.15603850325 3.8925250489999996 4.4195519574999995 ZT12-15 4.42471715175 4.119754905000001 4.7296793985 ZT16-19 5.58542366225 4.807195649500001 6.363651675 ZT20-23 8.080558985749999 7.8480164095 8.313101562