There would be 1/2 mL in each beaker.
We start by adding the amounts given by the line plot:
1/4 + 1/4 + 3/8 + 3/8 + 1/2 + 1/2 + 5/8 + 3/4 + 7/8
Find a common denominator. The smallest thing that 2, 4 and 8 will all evenly divide into is 8:
2/8 + 2/8 + 3/8 + 3/8 + 4/8 + 4/8 + 5/8 + 6/8 + 7/8
Add the numerators:
36/8
Now we divide this by 9:
36/8 ÷ 9 = 36/8 ÷ 9/1 = 36/8 × 1/9 = 36/72 = 1/2