hi, can anybody please explain to me the difference between these two? as i understand it: in normal backwardation you will experience a positive roll yield. at contract initiation t: F(t,T) that is futures prices must rise to meet the second condition… => F(T,T)/F(t,T)-1 = roll yield > 0 but how is this different from a regular price return? any help greatly appreciated 
For exam purposes, I think its safe to assume that you really only know need to know that roll yield is 1) Negative ( loss at settlement) for markets in contango 2) Positive (gains @ settlement ) for backwardation. My mnemonic “New Century Probable Bankruptcy” Try now to worry about the technicals and details of it. Hope this helps
Commodity contracts are derivatives and unlike stocks, they expire. Let’s say you bought a 1 month gold future for $10. If you want to keep this position when it expires, you have to buy another one “rolling over”. Let’s say the price of gold futures goes down to $8 when your contract expires in 1 month. Since you sold your expired contract for more than it cost to buy a new contract, there is a positive roll yield (backwardation). I’m guessing price return is just the most basic type of return that you see, like capital gains on a stock. Honestly I thought the reading on commodities in the curriculum was terrible and I really just reworded the first paragraph from this site. I wouldn’t spend too much time on commodities though, I doubt anybody knows anything about commodities based on that reading in the curriculum… Check out this site below for a good explanation of “roll yield” http://www.hardassetsinvestor.com/component/content/article/20/436.html?Itemid=4