condition mean min max ZT0-3 16.936366666666668 16.936366666666668 16.936366666666668 ZT4-7 13.656649999999999 13.656649999999999 13.656649999999999 ZT8-11 6.355684999999999 6.355684999999999 6.355684999999999 ZT12-15 6.79782 6.79782 6.79782 ZT16-19 14.1472 14.1472 14.1472 ZT20-23 15.347 15.347 15.347