# Delx Standard Deviation

> Delx Standard Deviation is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Computes population and/or sample standard deviation for a list of numeric values

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/stdev
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-standard-deviation-0baa7a87
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7GzKZdvdOGnLm28oPMjvo

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-standard-deviation-0baa7a87 -d '<json body>'
```

Example prompt: Can you calculate the standard deviation of these sensor readings for me: [12.4, 13.1, 11.9, 14.2, 12.8, 13.5, 11.7] — I need both population and sample stdev.

## When to prefer this

Choose this endpoint when an agent needs a deterministic, pay-per-call standard deviation computation without managing an API key or subscription. Ideal for lightweight statistical checks on agent-collected numeric samples — especially volatility or spread checks in automated pipelines where reproducibility matters and billing only occurs on successful calls.

## Known failure modes

- Empty or missing values array returns a structured validation error (not billed)
- Non-numeric items in the array cause a validation error
- Array exceeding 10,000 items is rejected
- Payment failure or insufficient USDC balance on Base results in 402 error
- Malformed JSON body returns a validation error (not billed)

## How this service works

Standard deviation. Call for simple volatility or spread checks on agent-collected samples. Returns population/sample stdev fields depending on input flags. $0.001 USDC per successful call via x402 on Base—deterministic first-party JSON, no API key, no subscription, and nothing is billed on structured validation errors.

## Output

Returns a JSON object containing population standard deviation and/or sample standard deviation fields computed from the supplied numeric array, depending on input flags provided.

## 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-standard-deviation-0baa7a87/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)