Source: https://guthlabs.ai/docs/instruments/sample-size-power-calculator-clinical-study-education/implementation/

instrument implementation / implementation-contract

# Sample Size / Power Calculator (clinical study education) implementation

A source-bound implementation contract for Sample Size / Power Calculator (clinical study education); deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t6-109

**Effect**: Computation or source lookup only

## Input and validation requirements

The edge vectors expose undefined or invalid outputs unless the calculator validates zero effect size and zero variance. The branch and convention probes also produce materially different sample sizes when outcome type or alpha sidedness is interpreted differently.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "design": "two-arm means, equal allocation",
    "sigma": 10,
    "sigma_units": "units",
    "delta": 5,
    "delta_units": "units",
    "alpha": 0.05,
    "power": 0.8,
    "z_(1-alpha/2)": 1.96,
    "z_power": 0.841621
  },
  "expected_outputs": {
    "raw_n_per_group": 62.792642,
    "required_n_per_group": 63
  },
  "working": "β=1−0.80=0.20. z-sum=1.96+0.841621=2.801621. Square: 2.801621²=7.849080. Variance factor: 2σ²/Δ²=2×10²/5²=200/25=8. Raw n=8×7.849080=62.792642. Round up: ceil(62.792642)=63 per group."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/sample-size-power-calculator-clinical-study-education/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/sample-size-power-calculator-clinical-study-education/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/sample-size-power-calculator-clinical-study-education/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche6/tranche6-results.json`