GIFSQ Tools · Module 12 — Sensory · Tool 227 of 500
Analyse a ranking test with the Friedman test: chi-square from the rank sums, degrees of freedom, and significance at α = 0.05.
Try sample values — fills the form with the worked example below.
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Friedman χ²
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Degrees of freedom
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Critical χ² (α = 0.05)
Equation: χ² = 12 ÷ (n·k·(k+1)) × ΣR² − 3n(k+1), where n = assessors, k = samples, R = rank sums; df = k − 1.
Method: ISO 8587:2006 ranking test; Friedman test with critical values from the chi-square distribution table (df 2 = 5.99).
Assumptions: Each assessor ranks every sample once with no ties; rank sums must add to n·k·(k+1) ÷ 2.
Limitations: A significant result shows the samples differ overall, not which pairs differ — follow with a post-hoc comparison.
Rounding: χ² to 2 decimal places; critical value from the chi-square table; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: ISO 8587:2006 ranking test; Friedman test with critical values from the chi-square distribution table (df 2 = 5.99).
Assumptions: Each assessor ranks every sample once with no ties; rank sums must add to n·k·(k+1) ÷ 2.
Limitations: A significant result shows the samples differ overall, not which pairs differ — follow with a post-hoc comparison.
Rounding: χ² to 2 decimal places; critical value from the chi-square table; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: 10 assessors, 3 samples, rank sums 15, 20, 25: χ² = 5.00, df = 2, critical 5.99 — not significant at α = 0.05.
Enter values above to see results.
Tool 227 of 500 — GIFSQ
