# Money Mind — Sample Size Calculator

> Money Mind — Sample Size Calculator is a paid API for AI agents from money-mind-extract.onrender.com, paid per call via x402, $0.31/call, status unknown (last checked 2026-10-18).

Computes the minimum number of observations required for a trading strategy test to have statistical power before running a backtest.

## Facts

- Endpoint: POST https://money-mind-extract.onrender.com/samplesize?utm_source=zero.xyz
- Price: $0.31/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/money-mind-sample-size-calculator-90777af9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_w2n6JEMreZLimW1S_2fzq

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 money-mind-sample-size-calculator-90777af9 -d '<json body>'
```

Example prompt: Before I run my backtest, can you check how many observations I actually need for the test to be statistically meaningful — I have a mean-reversion equity strategy with daily bars and want to detect a Sharpe of 0.5?

## When to prefer this

Use this endpoint when you want to validate data sufficiency BEFORE investing time or money in a full backtest — it acts as a cheap ($0.31) pre-flight check that tells you whether your observations are enough to detect a real edge at meaningful statistical power. Prefer this over running a full backtest blindly, especially when working with limited historical data, short time windows, or rare trade signals. It is not a substitute for the full multi-gate adjudication endpoint but is the fastest and cheapest first gate.

## Known failure modes

- Missing or malformed 'body' in the input object returns a validation error
- Insufficient test parameter details may produce a low-confidence or inconclusive verdict
- Payment failure via USDC on Base prevents the call from being processed
- Endpoint may time out or return 503 if the render.com host is cold-starting
- Ambiguous or underspecified strategy parameters may yield a generic rather than precise sample size estimate

## How this service works

Pay-per-call adjudication for trading research.
Eleven gates that killed 35 of our own concepts. Is your backtest real, is your
price data real, is your t-stat inflated? USDC on Base, no account needed.

## Output

Returns a JSON object with a 'reading' field containing a statistical interpretation and a 'verdict' field with a clear pass/fail or quantified recommendation on whether the dataset has enough observations for the test to be meaningful.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "description": "How many observations before this test can answer anything — ask before you spend"
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "reading": "...",
  "verdict": "..."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/money-mind-sample-size-calculator-90777af9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from money-mind-extract.onrender.com](https://www.zero.xyz/host/money-mind-extract.onrender.com/llms.txt)