The mean on this test is 3.5 with a standard deviation of .5. Billy scores 5. What is his Standard score?

Question

The mean on this test is 3.5 with a standard deviation of .5. Billy scores 5. What is his Standard score?

Answer 1

If I understand you correctly, his standard score is 5.  A standard deviation of .5 means that the test could be statistically off by up to .5 points...meaning that at the worst, he scores a 4.5 and the best a 5.5.  But, there's no way to tell, that's why they let you know the standard deviation.  Basically, it tells you how much you can rely on the score he was given.  It's a pretty small deviation, so I would say the test score is very accurate.