condition mean min max ZT0-3 14.705555 14.705555 14.705555 ZT4-7 15.016699 15.016699 15.016699 ZT8-11 12.960486 12.960486 12.960486 ZT12-15 14.9229185 14.9229185 14.9229185 ZT16-19 11.565218999999999 11.565218999999999 11.565218999999999 ZT20-23 12.952676 12.952676 12.952676