condition mean min max ZT0-3 2.76042 2.76042 2.76042 ZT4-7 1.71853 1.71853 1.71853 ZT8-11 2.861935 2.861935 2.861935 ZT12-15 3.20383 3.20383 3.20383 ZT16-19 3.4568950000000003 3.4568950000000003 3.4568950000000003 ZT20-23 2.5407 2.5407 2.5407