# Numora Chi-Square Test API

> Numora Chi-Square Test API is a paid API for AI agents from numormo.vercel.app, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-15).

Computes a chi-square goodness-of-fit or independence test given observed (and optionally expected) frequency arrays

## Facts

- Endpoint: POST https://numormo.vercel.app/api/statistics/chisquare
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/numora-chi-square-test-api-3d88fa7e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_e1689FSSjsa_BpkQci3lW

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability numora-chi-square-test-api-3d88fa7e -d '<json body>'
```

Example prompt: Run a chi-square goodness-of-fit test on my observed counts [50, 30, 20] against expected counts [40, 35, 25] and tell me the chi-square statistic and whether the result is statistically significant.

## When to prefer this

Use this endpoint when you need a quick, dependency-free chi-square computation without setting up a statistics library or data science environment. Ideal for AI agents that need on-the-fly hypothesis testing on categorical data with micropayment-based access. Prefer this over full stats platforms when you only need a single chi-square result and want deterministic, serverless math.

## Known failure modes

- Missing required 'observed' array returns a 400 error
- Mismatched array lengths between observed and expected cause a computation error
- Non-numeric values in arrays cause parsing errors
- Empty arrays return an error or undefined result
- Payment failure via x402 returns 402 Payment Required before computation

## How this service works

100 pure math computation endpoints for AI agents. Statistics, financial math, linear algebra, equation solving, calculus, number theory, sequence generation, and unit conversions. Zero external dependencies. x402 micropayments on Base.

## Output

Returns a JSON object with success: true, a result object containing the chi-square statistic, degrees of freedom, p-value, and whether the result is significant, plus a human-readable computation string describing what was calculated.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "observed"
 ],
 "properties": {
  "expected": {
   "type": "array"
  },
  "observed": {
   "type": "array"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "success",
  "result",
  "computation"
 ],
 "properties": {
  "result": {
   "type": "object",
   "description": "Computation result varies by endpoint"
  },
  "success": {
   "type": "boolean",
   "description": "Always true on success"
  },
  "computation": {
   "type": "string",
   "description": "Human-readable description of what was computed"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/numora-chi-square-test-api-3d88fa7e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from numormo.vercel.app](https://www.zero.xyz/host/numormo.vercel.app/llms.txt)