condition mean min max ZT0-3 2.3838425 2.086855 2.68083 ZT4-7 2.162925 2.162925 2.162925 ZT8-11 3.3457600000000003 3.3457600000000003 3.3457600000000003 ZT12-15 0 0 0 ZT16-19 3.5393999999999997 3.5393999999999997 3.5393999999999997 ZT20-23 3.366855 3.366855 3.366855