condition mean min max ZT0-3 0.4793538333333333 0.40090499999999996 0.623659 ZT4-7 0.1081415 0.1081415 0.1081415 ZT8-11 0.6825225 0.6825225 0.6825225 ZT12-15 0.20541775 0.173769 0.2370665 ZT16-19 0.32010799999999995 0.32010799999999995 0.32010799999999995 ZT20-23 0.301373 0.301373 0.301373