condition mean min max ZT0-3 1.3211206666666668 0.866897 2.023635 ZT4-7 0.7381465 0.7381465 0.7381465 ZT8-11 4.967385 4.967385 4.967385 ZT12-15 7.675655000000001 7.202075000000001 8.149235000000001 ZT16-19 6.965764999999999 6.965764999999999 6.965764999999999 ZT20-23 4.061265000000001 4.061265000000001 4.061265000000001