Correlation

{
  "asOf": "2026-10-11T06:26:06.329Z",
  "degraded": false,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "intercept": 2.2,
  "meanX": 3,
  "meanY": 4,
  "n": 5,
  "notChecked": [
    "causation (correlation never shows cause)",
    "non-linear relationships (a correlation near 0 can hide a strong curve)",
    "…2 more"
  ],
  "pearsonP": 0.12402706,
  "pearsonR": 0.774596669241,
  "prediction": {
    "extrapolating": true,
    "x": 6,
    "y": 5.8
  },
  "rSquared": 0.6,
  "reasons": [
    "Strength bands (0.2, 0.4, 0.6, 0.8) are a common convention, not a law.",
    "Correlation does not show cause.",
    "…1 more"
  ],
  "residualStandardError": 0.894427191,
  "slope": 0.6,
  "source": "computed locally",
  "spearmanP": 0.15461852,
  "spearmanRho": 0.737864787373,
  "summary": "n=5: Pearson r = 0.7746 (strong positive, p = 0.124), Spearman rho = 0.7379; y = 0.6x + 2.2, R squared 0.6; at x = 6, y is about 5.8.",
  "verdict": "STRONG_POSITIVE"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://math-stats.x402tookit.com/correlation?predictAt=6&x=1%2C2%2C3%2C4%2C5&y=2%2C4%2C5%2C4%2C5'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://math-stats.x402tookit.com/correlation?predictAt=6&x=1%2C2%2C3%2C4%2C5&y=2%2C4%2C5%2C4%2C5' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fmath-stats.x402tookit.com%2Fcorrelation
const res = await pay("https://math-stats.x402tookit.com/correlation?predictAt=6&x=1%2C2%2C3%2C4%2C5&y=2%2C4%2C5%2C4%2C5");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://math-stats.x402tookit.com/correlation?predictAt=6&x=1%2C2%2C3%2C4%2C5&y=2%2C4%2C5%2C4%2C5")
    print(res.status_code, res.text)