double-blind study - an experimental procedure in which neither the subjects of the experiment nor the persons administering the experiment know the critical aspects of the experiment; a double-blind procedure is used to guard against both experimenter bias and placebo effects.
No they get more expensive, airlines will always advise you to book in advance to take advantage of their best fares. Sometimes they do a special deal but not within a week of flying. I would try another airline or make different plans.
It really varies. Typically flight prices go up the closer to the flight date. But if it's close to the flight date and there are still seats available, then prices might go down during a seat sale in a final attempt to sell out the flight. I find it's really hard to predict flight prices. In most cases, I book as early as possible, and have always got the best price doing it that way.