condition mean min max ZT0-3 3.7177616666666666 1.978745 4.90075 ZT4-7 1.44519 1.44519 1.44519 ZT8-11 2.51957 2.51957 2.51957 ZT12-15 3.1381825 2.67809 3.598275 ZT16-19 2.75167 2.75167 2.75167 ZT20-23 4.967594999999999 4.967594999999999 4.967594999999999