Chi Square Test

{
  "asOf": "2026-10-11T08:55:55.262Z",
  "cellsWithExpectedBelow5": 0,
  "chiSquare": 13.4,
  "contributions": [
    2.5,
    0.4
  ],
  "degraded": false,
  "degreesOfFreedom": 5,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "expected": [
    10,
    10
  ],
  "notChecked": [
    "independence of observations (each subject counted once)",
    "random sampling",
    "…2 more"
  ],
  "pValue": 0.01990522,
  "reasons": [
    "All expected counts are at least 5.",
    "Statistic = sum of (observed - expected)^2 / expected; df = categories - 1."
  ],
  "significantAt5pct": true,
  "source": "computed locally",
  "summary": "Goodness of fit: chi-square 13.4, df 5, p = 0.01991: observed counts differ significantly from the expected pattern at the 5% level.",
  "test": "chi-square goodness of fit",
  "total": 60,
  "verdict": "SIGNIFICANT"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://stats-tests.x402tookit.com/chi-square-test?observed=5%2C8%2C9%2C8%2C10%2C20'

# 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://stats-tests.x402tookit.com/chi-square-test?observed=5%2C8%2C9%2C8%2C10%2C20' \
  | 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%2Fstats-tests.x402tookit.com%2Fchi-square-test
const res = await pay("https://stats-tests.x402tookit.com/chi-square-test?observed=5%2C8%2C9%2C8%2C10%2C20");
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://stats-tests.x402tookit.com/chi-square-test?observed=5%2C8%2C9%2C8%2C10%2C20")
    print(res.status_code, res.text)