condition mean min max ZT0-3 1.869165 1.67773 2.125185 ZT4-7 2.123315 2.123315 2.123315 ZT8-11 0.881417 0.881417 0.881417 ZT12-15 0.9645815 0.459588 1.469575 ZT16-19 0.9522485 0.9522485 0.9522485 ZT20-23 1.907351 1.907351 1.907351