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.
Price. If your goal is to book the cheapest flight possible, book early. Look for a ticket at least three weeks in advance for the best price. Prices go up once you're 14 days or less away from the flight date. Smart Money recommends looking for online deals on a Tuesday or Wednesday.