condition mean min max ZT0-3 5.508395 5.508395 5.508395 ZT4-7 4.668055 4.668055 4.668055 ZT8-11 5.3626249999999995 5.3626249999999995 5.3626249999999995 ZT12-15 7.554675 7.554675 7.554675 ZT16-19 8.98563 8.98563 8.98563 ZT20-23 5.378635 5.378635 5.378635