# PennyRail Basic Statistics

> PennyRail Basic Statistics is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Computes basic descriptive statistics (mean, median, variance, etc.) over a submitted array of numbers

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/number.stats--basic-statistics
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-basic-statistics-b3de3093
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QUhTYYS1VmWUA45u5KqXY

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 pennyrail-basic-statistics-b3de3093 -d '<json body>'
```

Example prompt: Can you compute basic statistics — mean, median, min, max, and standard deviation — on this array of numbers: [4, 7, 13, 2, 9, 15, 6, 11]?

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call computation of basic descriptive statistics on a numeric array without setting up a local statistics library or data science environment. Especially useful in agent pipelines where numeric summaries are needed on demand at low cost ($0.001/call).

## Known failure modes

- Empty or missing input array returns validation error
- Non-numeric values in array may cause computation error or be silently ignored
- Payment failure (402) if USDC payment header is missing or insufficient
- Malformed request body returns 400 error
- Very large arrays may time out depending on hosting limits

## How this service works

Machine-readable settlement service

## Output

A JSON object containing basic descriptive statistics computed over the input array, typically including measures such as mean, median, mode, min, max, count, range, variance, and standard deviation.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-basic-statistics-b3de3093/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pennyrail.vercel.app](https://www.zero.xyz/host/pennyrail.vercel.app/llms.txt)