Standard-score conversions API

Converts a raw score (or a z directly) across the full normalized standard-score family: z, T (M=50,SD=10), stanine, sten, IQ/deviation (M=100,SD=15), scaled (M=10,SD=3), and percentile. Answers 'What T-score / stanine / sten / IQ does this raw score map to?', 'What percentile is this z?'.

Price$0.04per request

MethodPOST

Route/v1/stats/standard-score-convert

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

psychometricsstandard-scoret-scorestaninesteniq-scorez-scorenorms

API URLhttps://x402.hexl.dev/v1/stats/standard-score-convert

Integration docs

Example request

{
  "raw": 130,
  "mean": 100,
  "sd": 15
}

Example response

{
  "z": 2,
  "tScore": 70,
  "iqScore": 130,
  "scaledScore": 16,
  "sten": 10,
  "stanine": 9,
  "percentile": 97.72,
  "interpretation": "very high (top ~2%)"
}

Input schema

{
  "type": "object",
  "properties": {
    "raw": {
      "type": "number",
      "examples": [
        130
      ]
    },
    "mean": {
      "type": "number",
      "examples": [
        100
      ]
    },
    "sd": {
      "type": "number",
      "examples": [
        15
      ]
    },
    "z": {
      "type": "number",
      "description": "alternative: supply z directly"
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}