Answer
Yes.
Work Step by Step
We know that the proportions are as follows:
Proportion of girls, probability
0, 1/8
1/3, 3/8
2/3, 3/8
1, 1/8
We know the sample proportion is $1/2$. Hence, using the table above, we find that the population proportion is:
$1/3(3/8)+2/3(3/8)+1/1(1/8)=0.5$
We see that the sample proportion is an unbiased predictor of the population proportion, because the sample and population proportions are the same.
