condition mean min max ZT0-3 8.1705725 7.4424600000000005 8.898685 ZT4-7 8.84567 8.84567 8.84567 ZT8-11 10.616530000000001 10.616530000000001 10.616530000000001 ZT12-15 0 0 0 ZT16-19 11.39315 11.39315 11.39315 ZT20-23 11.03265 11.03265 11.03265