{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://www.calculatorx.com/schemas/engineering.uncertainty.pooled_sd/1.0.0/input.json",
  "title": "Pooled standard deviation — input",
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "s": {
      "type": "array",
      "items": {
        "type": "number",
        "minimum": 0
      },
      "minItems": 2,
      "description": "Sample standard deviations s_i. Aliases: s_i, stdevs, std. Share-URL: comma-separated."
    },
    "nu": {
      "type": "array",
      "items": {
        "type": "number",
        "exclusiveMinimum": 0
      },
      "minItems": 2,
      "description": "Degrees of freedom ν_i, same length as s. Each ν_i > 0 and finite. Aliases: nu_i, dof, df. If omitted, n_i ≥ 2 gives ν_i = n_i−1."
    },
    "n": {
      "type": "array",
      "items": {
        "type": "number",
        "minimum": 2
      },
      "description": "Optional sample sizes. Used only when nu is omitted: ν_i = n_i−1."
    }
  },
  "required": [
    "s",
    "nu"
  ],
  "description": "Pooled s_p = √(Σ ν_i s_i² / Σ ν_i) from k≥2 stated sample standard deviations and their degrees of freedom. Not Type A from one sample, not Welch–Satterthwaite ν_eff, and not ISO 21748 u of a mean. (calculation_version 1.0.0)"
}