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.
1 When in doubt, booking earlier is safer. If you wait, fares could go up or down, and usually fares go up by more than they go down (read: going down $50 vs. going up by $300). Only bide your time if your flight isnât too full and you know the price is a lot higher than it should be.  Use online tools.