condition mean min max ZT0-3 5.944735 5.944735 5.944735 ZT4-7 3.7568200000000003 3.7568200000000003 3.7568200000000003 ZT8-11 4.658435 4.658435 4.658435 ZT12-15 6.938795000000001 6.938795000000001 6.938795000000001 ZT16-19 8.960015 8.960015 8.960015 ZT20-23 6.6475349999999995 6.6475349999999995 6.6475349999999995