Multiply σ by z to find deviation score (4 * 1.5 = 6) Transform z-scores into new X values with desired μ and σ values. The formula for calculating a z-score is is z = (x-μ)/σ, where x is the raw score, μ is the population mean, and σ is the population standard deviation. As the formula shows, the z-score is simply the raw score minus the population mean, divided by the population standard deviation.
