condition mean min max ZT0-3 10.159999999 10.159999999 10.159999999 ZT4-7 6.719444444333333 6.719444444333333 6.719444444333333 ZT8-11 6.633888889 6.633888889 6.633888889 ZT12-15 6.462222222 6.462222222 6.462222222 ZT16-19 7.791111111 7.791111111 7.791111111 ZT20-23 6.838888888666666 6.838888888666666 6.838888888666666