{
  "schema": "vedokrok.public-item.v1",
  "release_id": "MHC-RPUB-20260920-75ad787a",
  "url": "/knowledge/build-an-overall-rate-from-totals",
  "id": "MHC-D-RESEARCH-0251",
  "version": "0.1.0",
  "title": "Build an overall rate from totals",
  "summary": "Averaging the printed rates may average the wrong things.",
  "kind": "protocol",
  "body": "Return to the total quantity and the total time, distance or other denominator. Calculate the overall rate from those totals. The weighting follows the physical question, not the number of rows in the table.",
  "limits": [
    "Stops, idle time and excluded intervals must be treated consistently with the question."
  ],
  "topics": [
    "union-numerical-reasoning"
  ],
  "intents": [],
  "source_ids": [
    "RS-2876030F5763D7FA"
  ],
  "evidence": [
    {
      "claim": "An overall rate is calculated from the relevant total quantity divided by total exposure, such as distance divided by time.",
      "source_id": "RS-2876030F5763D7FA",
      "role": "supports",
      "note": "An unweighted average of component rates is appropriate only when its weighting matches the actual question.",
      "locator": "Derived quantities and units; independent rate derivation"
    }
  ],
  "use_when": [
    "You are combining speeds, throughput rates or other quantities measured per unit of exposure."
  ],
  "avoid_when": [
    "Stops, idle time and excluded intervals must be treated consistently with the question."
  ],
  "example": "Traveling 60 km at 30 km/h and 60 km at 60 km/h takes three hours for 120 km: the overall speed is 40 km/h, not 45.",
  "check": "The combined rate reproduces the actual total quantity over total exposure.",
  "steps": [
    "Name the quantity and denominator in the rate.",
    "Recover or obtain the totals for the entire interval.",
    "Divide once, then compare with any proposed average of component rates."
  ],
  "sources": [
    {
      "id": "RS-2876030F5763D7FA",
      "title": "Chemistry 2e, 1.4: Measurements",
      "url": "https://openstax.org/books/chemistry-2e/pages/1-4-measurements"
    }
  ],
  "relations": [],
  "collections": [
    {
      "id": "RC-D976097B2A42D9AC",
      "title": "Make the numbers answer the right question",
      "url": "/collections/make-the-numbers-answer-the-right-question"
    }
  ]
}