# Delx Commerce — Standard Deviation Calculator

> Delx Commerce — Standard Deviation Calculator is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-01).

Computes the population standard deviation (and mean, mode, count) for a supplied list of up to 10,000 numeric values, paid per-result in USDC via x402.

## Facts

- Endpoint: POST https://commerce.delx.ai/api/v1/x402/stdev?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-commerce-standard-deviation-calculator-bd5fd39a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Mm3iE2NCc6Qfwfoq1G6Cu

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 delx-commerce-standard-deviation-calculator-bd5fd39a -d '<json body>'
```

Example prompt: Calculate the standard deviation of these numbers for me: 2, 4, 4, 4, 5, 5, 7, 9.

## When to prefer this

Choose this endpoint when an AI agent needs a quick, pay-per-use statistical computation for standard deviation without setting up an account or subscription. Ideal for lightweight, one-off numerical analysis tasks where the agent already handles USDC payments via x402, and where integrating a full statistical library is overkill. Best for datasets up to 10,000 numbers requiring population standard deviation alongside mean and count.

## Known failure modes

- Empty or missing 'values' array returns a validation error
- Array exceeding 10,000 items is rejected with a size-limit error
- Non-numeric values in the array cause a type validation failure
- Insufficient USDC payment via x402 returns a 402 Payment Required response
- Single-element arrays may return stdev of 0 with no error

## How this service works

Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.

## Output

Returns a JSON object containing the population standard deviation ('stdev'), arithmetic mean ('mean'), sample count ('count'), the statistical mode used ('mode', e.g. 'population'), and a schema identifier ('schema': 'delx/stdev/v1').

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "sample": {
   "description": "Optional sample input."
  },
  "values": {
   "type": "array",
   "items": {
    "type": "number"
   },
   "maxItems": 10000,
   "minItems": 1,
   "description": "Numeric samples for stats tools (mean/median/stdev/percentile). Cap 10k numbers."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "mean": 6,
  "mode": "population",
  "count": 5,
  "stdev": 2.82842712474619,
  "schema": "delx/stdev/v1"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-commerce-standard-deviation-calculator-bd5fd39a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from commerce.delx.ai](https://www.zero.xyz/host/commerce.delx.ai/llms.txt)