condition mean min max ZT0-3 4.571831666666667 3.9939 4.92098 ZT4-7 3.681985 3.681985 3.681985 ZT8-11 19.02565 19.02565 19.02565 ZT12-15 22.95535 20.3008 25.6099 ZT16-19 11.737079999999999 11.737079999999999 11.737079999999999 ZT20-23 6.32686 6.32686 6.32686