condition mean min max ZT0-3 11.473328 11.473328 11.473328 ZT4-7 12.494349 12.494349 12.494349 ZT8-11 11.8146325 11.8146325 11.8146325 ZT12-15 11.836202499999999 11.836202499999999 11.836202499999999 ZT16-19 11.245777 11.245777 11.245777 ZT20-23 11.6217425 11.6217425 11.6217425