Description
Return sample/catch, and catch/sample with defined true for a positive sample, otherwise expansionFactor zero with defined false.
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 sample/catch, and catch/sample with defined true for a positive sample, otherwise expansionFactor zero with defined false.
When to use this tool
Use Catch Sample Selection Factor when you need a bounded sample-count or expansion component.
How to use the tool and how it works
- Enter sampleCount, catchCount. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read selectionFraction, expansionFactor, defined. Inspect defined before interpreting the associated values.
Require positive catchCount and sampleCount within it. Return sample/catch, and catch/sample with defined true for a positive sample, otherwise expansionFactor zero with defined false.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| sampleCount | Sample Count | Required. Safe integer; minimum 0. |
| catchCount | Catch Count | Required. Safe integer; minimum 1. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| selectionFraction | Selection Fraction | Required. Finite number. |
| expansionFactor | Expansion Factor | Required. Finite number. |
| defined | Whether the associated ratio has its required denominator; inspect before using a zero placeholder. | Required. Boolean. |
{
"input": {
"sampleCount": 10,
"catchCount": 100
},
"output": {
"selectionFraction": 0.1,
"expansionFactor": 10,
"defined": true
}
}Limitations and assumptions
- Zero expansion is a placeholder; a nonzero sampling fraction does not establish random selection, representativeness, or unbiased population expansion.
- 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
- Fish Egg Density Subsample Factor
Expand eggs by totalVolume/countedVolume and divide by filteredWaterVolume.
- Fish Length Frequency One Bin Density
Return count/total, that fraction divided by bin width, and count/sampledFraction.