Red Marble?

You have a bag with 7 marbles, 6 are blue and 1 is red. 7 people will choose, one at a time, trying to avoid the red marble. Is there any advantage to when you choose? (1st , last or other) Some say last since that allows everyone else to take their 1 in 7 chance before you, therefore increasing the chances one of them will get it before you. Others feel it makes no difference, since the odds are 1 in 7 for every one.

It doesn't matter what position you take.  Everyone, no matter what position, has a 1/7 chance to draw the red marble.  Think about it like this: If you go last, and the first six choose before you, but no one reveals what color they have, what are the odds that you draw the red marble on the final draw?  1/7.  You don't know if anyone got it first.  But going last makes it like this:  6 draws are made before yours.  Your draw is only 1 draw.  there's a 6/7 chance that ANYONE ELSE will get the red marble.  There's a 1/7 chance that YOU will get the red marble.  6/7 + 1/7 = 100% chance of SOMEBODY getting the red marble.

Just like on Deal or No Deal, where there's a constant 1/26 chance that the contestant has the million-dollar case, no matter how many have been eliminated.  The odds that they flash on the screen from time to time are bullshit that's dumbed down so that the American part of the audience feels like they understand it.