To find to mean of each you would just add the data together and divide by how many numbers there are
1.1+2+2+4+4+8+8+14+20=63 divide 63 by 9 because there are 9 numbers in this data bass 63/9=7, mean=7
2.16+16+19+20+20+21+21+22+22+22+23+26+26+26+28=306 divide 306 by 15 becuase there are 15 numbers in the data bass 306/15=20, mean=20
to find the difference just subtract 20 from 7, 20-7=13, 13 is the difference
Hope this helps have a nice nite!