The formula to find a raw score is x = x_bar + z * s. X represents the raw score, x_bar is the mean, z is the z-score and s is the standard deviation. To determine the raw score, these values must be known.
The raw score allows students to find their letter grades on curved tests. For example, if a test has a score of 45 out of 60, this must be converted to have any significance. Finding the z-score, mean and standard deviation allows a student to determine his raw score and where on the A-to-F grading scale he ranks.