How do I... COMPUTE VARIABLES in Jamovi? (2022)

Summary

The tutorial demonstrates how to create a computed variable in Jamovi by calculating an average from existing variables. The example dataset includes a previously reverse-coded cat-preference measure. The tutorial uses the relevant dog-preference variables to create an average preference score.

Creating the computed average

1. In the data view, choose New computed variable rather than entering data directly or creating a transform variable.
2. Name the new variable and, optionally, add a description.
3. In the formula editor, select the mean function. Jamovi’s function help explains the required format.
4. Add the existing variables to the function, separated by commas. In the example, these are Dog’s Best and Dog Love.
   • Variable names may appear in backticks, especially when they contain spaces or punctuation. This is normal.
5. Confirm the formula. Jamovi calculates the mean for each row and displays the results as a new variable.
   • The mean function ignores missing values.
   • The presenter notes that the function’s minimum number of valid values is zero.
   • As a check, values of 1 and 5 produce an average of 3.

Other functions mentioned

The presenter briefly surveys Jamovi’s built-in formula functions, including:

• Math: Absolute value, exponent, natural logarithm, base-10 logarithm, and square root.
• Statistical: Interquartile range and z-score functions, Box–Cox transformation, maximum, mean, minimum, median, mode, rank, rounding, standardization, standard deviation, sum, variance, standard error, and case-count functions.
• Logic: IF, ELSE IF, missing-value checks, and NOT.
• Text: Functions for containing, splitting, and converting text, as well as lookup and matching functions.
• Miscellaneous and sampling: Filtering, conversion to integer, offset, row functions, and sampling or simulation functions.

The function list in the editor provides usage formats and descriptions to help users construct formulas.

Speakers and sources

• Speaker: Tutorial presenter, identified with the channel as Alexander Swan, Ph.D.
• Featured source/tool: Jamovi 2.2.5, including its data view and built-in formula-function help.