condition mean min max ZT0-3 7.600149 7.600149 7.600149 ZT4-7 7.707693 7.707693 7.707693 ZT8-11 7.664121 7.664121 7.664121 ZT12-15 7.133395 7.133395 7.133395 ZT16-19 7.4173245 7.4173245 7.4173245 ZT20-23 7.630473 7.630473 7.630473