condition mean min max ZT0-3 2.43431 2.17564 2.69298 ZT4-7 2.487025 2.487025 2.487025 ZT8-11 2.732635 2.732635 2.732635 ZT12-15 0 0 0 ZT16-19 2.3514150000000003 2.3514150000000003 2.3514150000000003 ZT20-23 3.04014 3.04014 3.04014