First, I would like to say that if you choose to answer the homework in essay form rather than just one or two sentences per question, that's fine. What I am really looking for is a clear statement saying "this is what I think the answer to the question is." Make sure you include all of the points that you think are important.
a.
1. What do you think is the hypothesis?
The hypothesis is that the ice caps are being reduced by global warming.
2.Was there a hypothesis before the collection of data began you think or did it change as a result of the data?
There didn't appear to be a hypothesis before the data collection began, but if there were some form of a hypothesis, it was changed because of the idea of global warming.
3. Are the data of a quantitative nature, do you have confidence in their reliability?
The data is measuring the quantity of area covered by the ice, so yes, it is quantitative. I am confident in the reliability because I don't think there can be very much error in measuring the area covered.
4. Are there potential problems or changes in data collection you could think of that would affect the results?
The area covered by the ice is measured, but not the volume or mass, perhaps the ice is being compacted, or is layering so it is not spread out thinly.
Perhaps the satellite technology has been changed and the older data weren't as highly resolved or the cameras were not as good.
b. Is the link between the hypothesis and the measured result a direct or indirect link in your mind?
It is indirect because there are other reasons listed in the paper that could also cause the ice cover to be reduced.
c. One of the perhaps surprising results is that the decline in the winter ice cover is much less severe. Can you think of possible reasons for this?
Higher temperatures in the summer cause more melting, but higher temperatures in the winter are still below freezing, so the ice can recover. The Sun doesn't rise on the northern ice cap during the winter.
d. I the coverage of the arctic sea ice is so much smaller during the summer than during the winter, why doesn't the sea water rise during the summer?
Think of ice in your water glass... the ice takes up more volume than the same mass of ice so it floats on top, but when it melts, the water fills in the space where the ice under the water was before. The Arctic ice cap is not sitting on any land as the Antarctic ice cap is, so it is just ice floating on water and acts like the ice melting in your water glass.