Use Calculate Z-Score

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A z-score refers to the number of standard deviations each data value is from the mean, with a z-score of zero indicating the exact mean. Z-scores are useful for analyzing numbers in the context of the rest of the field.

To learn more about z-scores, see What is a z-score? What is a p-value?.

Example

A GIS analyst for a nongovernmental organization is analyzing a disease outbreak. Calculate Z-Score can be used to determine the areas where the outbreak is concentrated.

Run Calculate Z-Score

Use the following steps to calculate a z-score:

  1. Create a map, chart, or table using the dataset with which you want to calculate the z-score.
  2. Click the Action button Action.
  3. Do one of the following:
    • For chart and table cards, click How is it distributed in the Analytics pane.
    • For a map card, click the Find answers tab and click How is it distributed.
  4. Click Calculate Z-Score.
  5. For Choose a layer, select the dataset to use to calculate the z-score.
  6. For Choose number field, choose the field to use to calculate the z-score.

    The field must be a number or rate/ratio.

  7. Expand Additional options and provide values for Mean and Standard Deviation if necessary.

    If no values are provided, the mean and standard deviation are automatically calculated.

  8. For Name the result field, provide a name for the new field.
  9. Click Run.

Usage notes

To access Calculate Z-Score, click the Action button Action under How is it distributed on the Find answers tab. The input layer can be a point, a line, or an area layer.

A number field must be specified as the field to calculate the z-score. The number field is used in the (number-average)/standard_deviation equation.

You can provide mean and standard deviation values. If you don't provide values, the mean and standard deviation is automatically calculated.

Calculate Z-Score adds a new number field to the input layer. The field name is automatically populated in the Calculate Z-Score pane, but you can change it before running the calculation.