condition mean min max ZT0-3 9.615812 9.615812 9.615812 ZT4-7 8.9442775 8.9442775 8.9442775 ZT8-11 9.4050775 9.4050775 9.4050775 ZT12-15 9.161025500000001 9.161025500000001 9.161025500000001 ZT16-19 9.5808775 9.5808775 9.5808775 ZT20-23 9.218377 9.218377 9.218377