condition mean min max ZT0-3 6.4557 6.4557 6.4557 ZT4-7 4.45892 4.45892 4.45892 ZT8-11 6.555009999999999 6.555009999999999 6.555009999999999 ZT12-15 6.7140249999999995 6.7140249999999995 6.7140249999999995 ZT16-19 7.211555 7.211555 7.211555 ZT20-23 6.41934 6.41934 6.41934