# SignalDesk AI – Pearson Correlation

> SignalDesk AI – Pearson Correlation 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 Pearson correlation coefficient between two numeric arrays

## Facts

- Endpoint: POST https://x402-agent.kariguetoazul.workers.dev/api/stats/correlation?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-pearson-correlation-9a3eedd0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_b_INu7d6imyLtO3EYvFmN

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-pearson-correlation-9a3eedd0 -d '<json body>'
```

Example prompt: Can you calculate the Pearson correlation between these two datasets: X = [1, 2, 3, 4, 5] and Y = [2.1, 4.0, 5.9, 8.1, 10.0]?

## When to prefer this

Choose this endpoint when you need a quick, paid, serverless Pearson r computation without running your own statistical library — particularly useful in agent pipelines where you want an auditable, bounded-cost statistic call on two numeric series of up to 1000 observations each.

## Known failure modes

- Arrays of unequal length may cause an error or undefined behavior
- Arrays with fewer than 2 items will be rejected (minItems: 2)
- Arrays with values exceeding ±1e15 will be rejected by schema validation
- Zero-variance arrays (all identical values) may produce NaN or division-by-zero
- Payment failure (x402) will block execution if USDC balance is insufficient

## 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 Pearson r value (a float between -1 and 1), where 1 indicates perfect positive linear correlation, -1 perfect negative, and 0 no linear relationship.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "x": {
   "type": "array",
   "items": {
    "type": "number",
    "maximum": 1000000000000000,
    "minimum": -1000000000000000
   },
   "maxItems": 1000,
   "minItems": 2,
   "description": "At least two observations."
  },
  "y": {
   "type": "array",
   "items": {
    "type": "number",
    "maximum": 1000000000000000,
    "minimum": -1000000000000000
   },
   "maxItems": 1000,
   "minItems": 2,
   "description": "At least two observations."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "pearson_r": 1
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signaldesk-ai-pearson-correlation-9a3eedd0/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)