How to Perform Mathematical Calculations on Variables

This article describes how to perform basic mathematical functions on variables in Displayr using the Calculation menu. These functions include Divide, Multiply, Subtract, Average, Sum, Maximum, Minimum, Any of, None of, Count, Standard Deviation, and Variance.

Requirements

• A Displayr document with a data set.
• Numeric variables. In this example, we have a numeric grid variable set called Q2 - No. of colas consumed which we will use for these calculations:

Method - Divide, Multiply, Subtract

1. Select one or two variables in the Data Sets tree that you wish to use in your calculation. For example, let's select the Coca-Cola - When 'out and about' and Coca-Cola - When 'at home' variables. Note, the order you select these variables determines where they are placed in the calculation.

2. Go to Calculation > Divide/Multiply or Subtract in the toolbar.

3. A new variable will be created directly after the selected variable set(s) which applies the specified formula on the selected variable(s).

4. OPTIONAL: When you select the new variable, in the object inspector it will display the variables that have been used. You can change the variables by using the relevant drop-down.

5. OPTIONAL: If you only select a single variable, it will default to a Single numeric value of 1 for the second reference. You can change this value as required to update your calculation.

6. OPTIONAL: You can additionally switch either reference between a Variable and a Single numeric value if required.

Note, if you perform this on nominal variables, the calculation will use the underlying values.

Method - Average, Sum, Maximum, Minimum, Any of, None of, Count, Standard Deviation, Variance

1. Select the variables in the Data Sets tree that you wish to use in your calculation. For example, let's select all the Coca-Cola variables from the When 'out and about' group. Note, the order you select these variables determines where they are placed in the calculation.

2. Go to Calculation in the toolbar and select Average, Sum, Maximum, Minimum, Any of, None of, Count, Standard Deviation or Variance in both sub-menus, e.g. Average > Average.

3. A new variable will be created directly after the selected variable set(s) which applies the specified formula on the selected variable(s).

4. OPTIONAL: When you select the new variable, in the object inspector it will display the variables that have been used. You can change, remove or add to the variables drop-down as required:

5. OPTIONAL: Untick Calculate for observations with incomplete data if you wish to return missing for any record that has missing data in any of the selected variables.

6. OPTIONAL: For the Any of, None of and Count options where you are working with numeric data, you can additionally adjust Values to count. This takes the format of individual specified values or a range of values, e.g. 0-10 or 1,2,3 or >1. When working with categorical data, you instead specify the Categorical labels to include.

See Also

How to Create a Custom R Text Variable

How to Create a Custom Numeric R Variable

How to Perform Mathematical Calculations on Tables

How to Perform Mathematical Calculations Using R