Description
Return (1/3)^correct × (2/3)^(trials-correct) and its natural logarithm using log-domain arithmetic.
A sensory triangle trial asks a participant to distinguish one different sample among three. Guessing models distinguish one particular response sequence from the probability of a total count of correct responses and from a test's tail probability.
Return (1/3)^correct × (2/3)^(trials-correct) and its natural logarithm using log-domain arithmetic.
When to use this tool
Use Sensory Triangle Test Guess Probability Term when you need the exact probability term under the supplied one-third guessing model.
How to use the tool and how it works
- Enter trials, correct. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read guessProbability, logProbability. Use the output convention below.
Require trials 0-1000000 and correct 0-trials. Return (1/3)^correct × (2/3)^(trials-correct) and its natural logarithm using log-domain arithmetic.1
A binomial count probability includes the number of success-position arrangements. This tool deliberately returns only the product for one specified response sequence.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| trials | Trials | Required. Safe integer; minimum 0; maximum 1000000. |
| correct | Correct | Required. Safe integer; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| guessProbability | Probability of one specified success/failure sequence; excludes the binomial coefficient. Unit: 1. | Required. Finite number. |
| logProbability | Natural log of that sequence probability; remains useful when exponentiation underflows. Unit: 1. | Required. Finite number. |
{
"input": {
"trials": 1,
"correct": 1
},
"output": {
"guessProbability": 0.3333333333333333,
"logProbability": -1.0986122886681098
}
}Limitations and assumptions
- This is one specified binary success/failure sequence probability under independent one-third guessing, not the binomial count probability or a significance-test tail; no combinatorial factor is included.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use a complete sensory-test analysis with the intended experimental design and statistical test. Check independence, randomization and the difference between sequence, count and tail probabilities.
References
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