GIFSQ Tools · Module 12 — Sensory · Tool 225 of 500
Analyse a duo-trio test: the exact one-sided binomial p-value against the 1-in-2 guessing chance, and the minimum correct count for significance at α = 0.05.
Try sample values — fills the form with the worked example below.
–
p-value
–
Minimum correct (α = 0.05)
–
Expected by chance
Equation: p = Σ C(n,k)(1/2)^k(1/2)^(n−k) for k = correct … n; critical value = smallest correct count with p ≤ 0.05.
Method: ISO 10399:2017 duo-trio test; exact binomial test with guessing probability p = 1/2.
Assumptions: Each assessor matches one coded sample to the reference; responses are independent.
Limitations: A significant result shows a perceivable difference, not how large it is; the reference must be clearly identified to assessors.
Rounding: p-value to 4 decimal places; critical value is a whole number; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: ISO 10399:2017 duo-trio test; exact binomial test with guessing probability p = 1/2.
Assumptions: Each assessor matches one coded sample to the reference; responses are independent.
Limitations: A significant result shows a perceivable difference, not how large it is; the reference must be clearly identified to assessors.
Rounding: p-value to 4 decimal places; critical value is a whole number; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: 20 assessors, 15 correct: p = 0.0207, minimum correct 15, expected by chance 10.00 — significant at α = 0.05.
Enter values above to see results.
Tool 225 of 500 — GIFSQ
