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Bone Density Z-Score Calculator

Formula

The formula to calculate the Bone Density Z-Score (Z) is:

$Z = \frac{D - \mu}{\sigma}$

Where:

Z – The Z-Score.
D – The measured bone density (g/cm²).
μ – The population mean bone density (g/cm²).
σ – The standard deviation (g/cm²).

Definition

Bone Density Z-Score (Z): A statistical measure that compares an individual’s bone density to the average bone density of a population of the same age, sex, and ethnicity.
Measured Bone Density (D): The bone density measured in g/cm².
Population Mean Bone Density (μ): The average bone density of the reference population in g/cm².
Standard Deviation (σ): The standard deviation of the bone density in the reference population in g/cm².

Example

Let's say the measured bone density (D) is 1.2 g/cm², the population mean bone density (μ) is 1.0 g/cm², and the standard deviation (σ) is 0.1 g/cm². Using the formula:

$Z = \frac{1.2 - 1.0}{0.1} = 2$

So, the Z-Score is 2.