# SignalDesk AI Population Variance Calculator

> SignalDesk AI Population Variance Calculator is a paid API for AI agents from x402-agent.kariguetoazul.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-13).

Computes the population variance (and denominator) for a given array of up to 1000 numeric observations

## Facts

- Endpoint: POST https://x402-agent.kariguetoazul.workers.dev/api/stats/population-variance?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signaldesk-ai-population-variance-calculator-70baf625
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_F7itsRlmP6-HloRxpG-C3

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 signaldesk-ai-population-variance-calculator-70baf625 -d '<json body>'
```

Example prompt: Can you calculate the population variance for these 5 measurements: 2, 4, 4, 4, 5, 5, 7, 9?

## When to prefer this

Choose this endpoint when you need a quick, inexpensive population variance computation (not sample variance) for up to 1000 numeric values without running local code. It is ideal for AI agents that need a verifiable, server-side statistical result billed per-call at $0.001 USDC via x402. Prefer this over client-side computation when auditability or reproducibility of the result matters, or when the agent environment lacks math libraries.

## Known failure modes

- Empty or missing 'values' array returns a validation error
- More than 1000 items in the array exceeds maxItems limit and is rejected
- Non-numeric or non-finite values (NaN, Infinity) may be rejected or cause errors
- Values outside the allowed range (-1e15 to 1e15) will be rejected
- Insufficient USDC balance or x402 payment failure results in a 402 Payment Required response
- Network timeout on Cloudflare Worker edge node

## How this service works

Evidence-backed autonomous AI jobs and paid data tools. Queue/D1/cron run outside the chat; free quotas and bounded execution apply.

## Output

Returns a JSON object containing the computed population variance as a float (e.g. 0.6666...) and the denominator (N, the count of observations) used in the calculation, confirming it is population variance rather than sample variance.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "values": {
   "type": "array",
   "items": {
    "type": "number",
    "maximum": 1000000000000000,
    "minimum": -1000000000000000
   },
   "maxItems": 1000,
   "minItems": 1,
   "description": "Up to 1000 finite observations."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "variance": 0.6666666666666666,
  "denominator": 3
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signaldesk-ai-population-variance-calculator-70baf625/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-agent.kariguetoazul.workers.dev](https://www.zero.xyz/host/x402-agent.kariguetoazul.workers.dev/llms.txt)