condition mean min max ZT0-3 3.519878333333333 2.460745 4.64077 ZT4-7 2.040515 2.040515 2.040515 ZT8-11 2.896875 2.896875 2.896875 ZT12-15 4.92238 4.41038 5.43438 ZT16-19 6.43253 6.43253 6.43253 ZT20-23 7.75417 7.75417 7.75417