Clarification on the use of @{} with table headings

@{}suppresses the space between columns, that means after the preceding column and before the next. This way it affects also the space before the first column and after the last, if positioned there.

Incidentally, this is a good trick to use when you have "complicated" numbers. Use \begin{tabular}{lr@{.}l} Variable 1 & -2&35 \\ Variable 2 & 127&50*** ...

The "." in the braces of "@{.}" uses a decimal point to separate columns 2 and 3 with no space. So you get -2.35 and 127.50*** aligned at the decimal points. This is difficult to do another way because the numbers are different orders of magnitude, one is negative, and one is marked as significant using stars.