# Numora Chi-Square Statistics Endpoint

> Numora Chi-Square Statistics Endpoint is a paid API for AI agents from numomo.vercel.app, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14).

Computes a chi-square goodness-of-fit or independence test given observed (and optionally expected) frequency arrays, returning the test statistic, p-value, and degrees of freedom.

## Facts

- Endpoint: POST https://numomo.vercel.app/api/statistics/chisquare
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/numora-chi-square-statistics-endpoint-1f4efe8f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_flYYoVD4Olf_UTHajTQ6b

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-statistics-endpoint-1f4efe8f -d '<json body>'
```

Example prompt: Run a chi-square goodness-of-fit test on these observed counts [120, 85, 95] against the expected counts [100, 100, 100] and tell me the chi-square statistic, p-value, and degrees of freedom.

## When to prefer this

Choose this endpoint when you need a fast, serverless, zero-dependency chi-square statistical test without setting up a Python/R environment or calling a heavyweight analytics platform. Ideal for AI agents that need on-the-fly hypothesis testing for categorical data, A/B test evaluation, or goodness-of-fit checks within a pipeline. The micropayment model via x402 on Base makes it suitable for pay-per-use agent workflows.

## Known failure modes

- Missing 'observed' array returns a 400 validation error
- Observed and expected arrays of mismatched lengths may cause a computation error
- Expected frequencies containing zeros can cause division-by-zero issues
- Arrays with fewer than 2 categories may produce degenerate results
- Non-numeric values in arrays will likely return an error response

## 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 a boolean 'success' field, a human-readable 'computation' string describing what was calculated, and a 'result' object containing the chi-square test statistic, degrees of freedom, p-value, and potentially a significance conclusion.

## 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-statistics-endpoint-1f4efe8f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from numomo.vercel.app](https://www.zero.xyz/host/numomo.vercel.app/llms.txt)