Description
Return count/total, that fraction divided by bin width, and count/sampledFraction.
A subsample fraction, histogram bin, or counted category describes a selected part of a larger fisheries record. Expansion and relative frequency have different denominators and require explicit sampling assumptions.
Return count/total, that fraction divided by bin width, and count/sampledFraction.
When to use this tool
Use Fish Length Frequency One Bin Density when you need a bounded sample-count or expansion component.
How to use the tool and how it works
- Enter count, total, lowerLength, upperLength, sampledFraction. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read relativeFrequency, density, expandedCount. Use the output convention below.
Require positive total, count within it, increasing length-bin bounds, and sampledFraction in (0, 1]. Return count/total, that fraction divided by bin width, and count/sampledFraction.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| count | Count under the stated selection and duplicate convention. | Required. Safe integer; minimum 0. |
| total | Total | Required. Safe integer; minimum 1. |
| lowerLength | Lower Length | Required. Finite number. |
| upperLength | Upper Length | Required. Finite number. |
| sampledFraction | Sampled Fraction | Required. Finite number; maximum 1; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| relativeFrequency | Relative Frequency | Required. Finite number. |
| density | Relative frequency per input length unit, not fish per geographic area. | Required. Finite number. |
| expandedCount | Expanded Count | Required. Finite number. |
{
"input": {
"count": 20,
"total": 100,
"lowerLength": 10,
"upperLength": 15,
"sampledFraction": 0.5
},
"output": {
"relativeFrequency": 0.2,
"density": 0.04,
"expandedCount": 40
}
}Limitations and assumptions
- Density is relative frequency per length unit, not fish per area; expandedCount uses a supplied sampling fraction and may be fractional.
- 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 documented sampling design and assess representativeness, detection, and uncertainty before making population estimates.
References
Similar or alternative tools
- Catch Sample Selection Factor
Return sample/catch, and catch/sample with defined true for a positive sample, otherwise expansionFactor zero with defined false.
- Fish Egg Density Subsample Factor
Expand eggs by totalVolume/countedVolume and divide by filteredWaterVolume.