Professional Detailing1 min read

Range and Interquartile Range in Coating Trials: Different Views of Variation

The full range describes the distance between the smallest and largest observations. The interquartile range describes the middle half under the chosen quartile convention. Both can be useful, but they answer different questions.

Updated · NANOLAB Knowledge

The key distinction

A summary focused on the middle should not hide extreme observations that matter to acceptance. State the convention and preserve individual values where the dataset is small.

Practical checks

  1. Identify the spread measure used.
  2. Report sample count and relevant extreme results.
  3. Keep the calculation convention consistent across comparisons.

Example

Illustrative example: one unusual result can expand the full range while leaving the middle half relatively similar. That does not make the unusual result invalid or justify removing it.

Scope and limits

Do not select whichever spread measure makes a coating appear most consistent. The analysis should match the question and the trial's established treatment of unusual observations.

Related guidance

Ask NANOLAB about the exact product and intended use. Use the current product documentation for formulation-specific instructions.