condition mean min max ZT0-3 2.1229983333333333 1.609025 2.625165 ZT4-7 1.2294049999999999 1.2294049999999999 1.2294049999999999 ZT8-11 1.28958 1.28958 1.28958 ZT12-15 0.7602577500000001 0.7437155 0.7768 ZT16-19 1.06027 1.06027 1.06027 ZT20-23 1.97776 1.97776 1.97776