condition mean min max ZT0-3 3.621325 2.9706099999999998 4.249555 ZT4-7 4.79399 4.79399 4.79399 ZT8-11 4.59431 4.59431 4.59431 ZT12-15 4.63719 4.20729 5.06709 ZT16-19 4.114089999999999 4.114089999999999 4.114089999999999 ZT20-23 4.00943 4.00943 4.00943