condition mean min max ZT0-3 0.563057 0.563057 0.563057 ZT4-7 0.486186 0.486186 0.486186 ZT8-11 0.396691 0.396691 0.396691 ZT12-15 0.6957074999999999 0.6957074999999999 0.6957074999999999 ZT16-19 0.764492 0.764492 0.764492 ZT20-23 0.744542 0.744542 0.744542