New South Wales
Here are the appropriate rules quotes:
RRG - Conflicts (p2) wrote:
It is possible for a game effect to have more than one possible
outcome. In such a case, investigators as a group determine the
outcome of that effect.
RRG - Range wrote:
The range of effects that use the phrase “within range” is up to three
• Range cannot be counted through walls or doors unless an effect
specifically allows it.
• Range can be counted through impassable borders.
RRG - Test wrote:
• A test declaration may include a number separated from the
skill icon by a semicolon. This is the test difficulty. The test
difficulty indicates the test result required to pass the test. If
the test result is less than the test difficulty, the investigator
fails the test.
As Mark points out, the key difference between (@;1) and (@) is that (@;1) will have a pass/fail result, while (@) will not have a pass/fail result and will likely only rely on a calculation based on the number of successes rolled.