condition mean min max ZT0-3 18.064169 18.064169 18.064169 ZT4-7 24.947954 24.947954 24.947954 ZT8-11 18.2133825 18.2133825 18.2133825 ZT12-15 20.026273 20.026273 20.026273 ZT16-19 20.700551 20.700551 20.700551 ZT20-23 20.769664 20.769664 20.769664