condition mean min max ZT0-3 2.187455 1.4972750000000001 2.77459 ZT4-7 1.3933499999999999 1.3933499999999999 1.3933499999999999 ZT8-11 1.414495 1.414495 1.414495 ZT12-15 4.39063 4.340755 4.440505 ZT16-19 4.367380000000001 4.367380000000001 4.367380000000001 ZT20-23 4.48824 4.48824 4.48824