condition mean min max ZT0-3 2.863385 2.863385 2.863385 ZT4-7 2.0694 2.0694 2.0694 ZT8-11 3.25465 3.25465 3.25465 ZT12-15 3.7034399999999996 3.7034399999999996 3.7034399999999996 ZT16-19 5.0499 5.0499 5.0499 ZT20-23 2.50296 2.50296 2.50296