condition mean min max ZT0-3 64.215301 64.215301 64.215301 ZT4-7 66.030733 66.030733 66.030733 ZT8-11 62.8108265 62.8108265 62.8108265 ZT12-15 62.10377150000001 62.10377150000001 62.10377150000001 ZT16-19 73.042727 73.042727 73.042727 ZT20-23 64.493585 64.493585 64.493585