# pv-chi-square

`station__pv-compute__pv-chi-square` · native (always callable) · domain `pv-compute` · pv-relevance `pv-core`

Calculate Chi-square

## Agent metadata

- `idempotent`: true
- `read_only`: true
- `expected_latency_ms`: 79 ms (last measured)
- `cost_tokens_estimate`: 137 tokens (~548 bytes)

## Compose with

After invoking this tool, a natural next step is [`station__calculate__compute-prr`](/tools/calculate__compute-prr). The recommended chain is hand-authored in the catalog's `pipes_to` graph.

## Input schema

- `a` *integer* (required) — Drug + event count (cell a of 2x2 table)
- `b` *integer* (required) — Drug + no-event count (cell b)
- `c` *integer* (required) — No-drug + event count (cell c)
- `d` *integer* (required) — No-drug + no-event count (cell d)
- `table` *object* — Optional alternate form: nest {a,b,c,d} inside a `table` key.

## Example call

```json
POST /api/mcp
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "station__pv-compute__pv-chi-square",
    "arguments": {
      "a": 0,
      "b": 0,
      "c": 0,
      "d": 0
    }
  }
}
```

## Related

- [/tools](/tools) — all 3062 tools
- [/tools/pv-compute__pv-chi-square](/tools/pv-compute__pv-chi-square) — HTML page
- [/tools/pv-compute__pv-chi-square/json](/tools/pv-compute__pv-chi-square/json) — JSON form (agent-friendly)
- [/api/mcp](/api/mcp) — endpoint
- [/AGENTS.md](/AGENTS.md) — agent guide