Z-Score from Mean and Standard Deviation

Equation: the z-score is z = (x − μ)/σ, the number of standard deviations a value lies from the mean. Values: x = 85 is the value being standardized. μ = 70 is the mean, at the peak of the curve. σ = 10 is the standard deviation, the distance from 70 to 80 on the plot. Step 1: distance from the mean, x − μ = 85 − 70 = 15. Step 2: z = 15/10 = 1.5. The value sits 1.5 standard deviations above the mean. Choosing 1.0 counts only whole tick marks, and 2.0 rounds up to the 90 tick.