How to find the range of a raw score?
First, you probably need more than one raw score. If you only
have one raw score then your range is one point, the (score - 1/2)
to the (score + 1/2). For a score of 80, the range would be from
79.5 to 80.5. It is kind of meaningless if you find a range for
just one score. You need a larger sample size. A better question
is: "How do I find the range of a sample of raw scores?" You need
all of the raw scores in your sample, not just one score. Because
each whole number (i.e., 80) represents a continuum (e.g., of
ability), the range goes from 1/2 a point below the lowest score to
1/2 a point above the highest score. Let's look at some fake data
with 5 participants: 10 20 30 40 50. The highest score is 50. The
lowest score is 10. The range is (10-.5) to (50+.5). The range of
raw scores is 9.5 to 50.5, a range of 41 points. If you are looking
for the easy answer, then the range is 10 to 50 (lowest score to
highest score; a range of 40 points). If you for some reason only
have one score (e.g., 80), the long answer is 79.5 to 80.5 (range
of one), the short answer is that there is no variability (range of
zero).