condition mean min max ZT0-3 0.674253 0.456212 0.916557 ZT4-7 0.4486275 0.4486275 0.4486275 ZT8-11 0.27518549999999997 0.27518549999999997 0.27518549999999997 ZT12-15 0.333287 0.292353 0.374221 ZT16-19 0.791923 0.791923 0.791923 ZT20-23 0.689512 0.689512 0.689512