condition mean min max ZT0-3 1.9756425 1.7818 2.169485 ZT4-7 2.6034100000000002 2.6034100000000002 2.6034100000000002 ZT8-11 3.47795 3.47795 3.47795 ZT12-15 8.139546666666668 5.23626 11.042833333333334 ZT16-19 5.46439 4.63822 6.29056 ZT20-23 0 0 0