Posted by dee on .
the mean is 3.5. dtandard deviation is .5. sally's score is 1.5 on test. how many standard deviations is she from the mean?
billy scores 5. what is his standard score?
what scale of measurement is being used? is it appropriate? why/why not?

standard deviation 
PsyDAG,
The Z score indicates standard deviations from the mean. It is accurate as long as the distribution is normal.
Z = (score  mean)/standard deviation
You can do the calculations.