The question isn't very clear, but I'll do my best to answer them anyways.
8) Median. Half of the cereal means the top or bottom half, so therefore $2.00 is the median.
9) Mean. Key word here is average.
10) Mode. "Most common" refers to the one that is expressed the most, thus mode.
11) Range. The problem talks about "varying", meaning the difference between the shortest and the tallest, and thus the range.
12) Mode. "Most common", similar to 10
13) Range. Key word here is varying, similar to 11
14) Median. "One-half" is the key word. See 8.