condition mean min max ZT0-3 0.993645 0.803354 1.1019465 ZT4-7 0.410149 0.410149 0.410149 ZT8-11 0.852209 0.852209 0.852209 ZT12-15 1.7627025 1.622355 1.90305 ZT16-19 1.955415 1.955415 1.955415 ZT20-23 1.5167199999999998 1.5167199999999998 1.5167199999999998