condition mean min max ZT0-3 764.505509 764.505509 764.505509 ZT4-7 883.271202 883.271202 883.271202 ZT8-11 569.741874 569.741874 569.741874 ZT12-15 591.984966 591.984966 591.984966 ZT16-19 253.7294585 253.7294585 253.7294585 ZT20-23 132.232045 132.232045 132.232045