Four of the following five are alike in a certain way based on the given arrangement and thus form a group. Which is the one that does not belong to that group?

As per the given above question , we have
P, Q, R, S, T, V and W are sitting in a straight line facing north. Each one of them lives on a different floor in the same building which is numbered from one to seven. Q sits fourth to the left of the person living on the 6th floor. Either Q or the person living on the 6th floor sits at the extreme ends of the line.
From above it is clear that Q person live on the 6th floor .