condition mean min max ZT0-3 508.994599 508.994599 508.994599 ZT4-7 768.7616634999999 768.7616634999999 768.7616634999999 ZT8-11 687.046423 687.046423 687.046423 ZT12-15 641.3513455 641.3513455 641.3513455 ZT16-19 516.2735465000001 516.2735465000001 516.2735465000001 ZT20-23 276.901198 276.901198 276.901198