Evidence row 2201577

What was observed

{
  "endpoints": [
    [
      "x402",
      "https://math-stats.x402tookit.com/sample-size"
    ]
  ],
  "name": "Math and Statistics",
  "owner_address": "0xb531320805c5bed1d46aeadcf4f008fdf172dbda",
  "raw": {
    "accepts": [
      {
        "amount": "20000",
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "maxTimeoutSeconds": 300,
        "network": "eip155:8453",
        "payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
        "scheme": "exact"
      },
      {
        "amount": "20000",
        "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
        "extra": {
          "feePayer": "D6ZhtNQ5nT9ZnTHUbqXZsTx5MH2rPFiBBggX4hY1WePM",
          "transactionVersions": [
            0
          ]
        },
        "maxTimeoutSeconds": 300,
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "payTo": "DUPiupXtuox38dcGoXUKer5mAydCzmaHjrbQ66qeEm8s",
        "scheme": "exact"
      },
      {
        "amount": "20000",
        "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "maxTimeoutSeconds": 300,
        "network": "eip155:137",
        "payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
        "scheme": "exact"
      },
      {
        "amount": "20000",
        "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "maxTimeoutSeconds": 300,
        "network": "eip155:42161",
        "payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
        "scheme": "exact"
      }
    ],
    "description": "Required sample size for a survey (margin of error, optional finite population) or an A/B test (baseline, lift, power).",
    "extensions": {
      "bazaar": {
        "info": {
          "input": {
            "method": "GET",
            "queryParams": {
              "confidence": 0.95,
              "margin": 0.05,
              "mode": "survey"
            },
            "type": "http"
          },
          "output": {
            "example": {
              "asOf": "2026-10-11T06:26:07.367Z",
              "confidence": 0.95,
              "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.",
              "finitePopulationApplied": false,
              "margin": 0.05,
              "notChecked": [
                "non-response (inflate the survey size by 1 / expected response rate)",
                "design effects from clustering or weighting",
                "…2 more"
              ],
              "proportion": 0.5,
              "reasons": [
                "Uses n = z squared times p(1-p) over margin squared; p = 0.5 is the worst case.",
                "Divide by your expected response rate to know how many people to invite."
              ],
              "required": 385,
              "source": "computed locally",
              "summary": "Survey for +/-5 points at 95% confidence (p=0.5): 385 respondents.",
              "unroundedInfinitePopulation": 384.146,
              "verdict": "SURVEY_SIZE",
              "z": 1.959964
            },
            "type": "json"
          }
        },
        "schema": {
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "additionalProperties": false,
              "properties": {
                "method": {
                  "enum": [
                    "GET"
                  ],
                  "type": "string"
                },
                "queryParams": {
                  "properties": {
                    "baseline": {
                      "description": "A/B baseline conversion rate, e.g. 0.10",
                      "type": "number"
                    },
                    "confidence": {
                      "description": "0.80 to 0.999 (default 0.95)",
                      "type": "number"
                    },
                    "margin": {
                      "description": "Survey margin of error as a fraction, e.g. 0.05",
                      "type": "number"
                    },
                    "mode": {
                      "description": "survey or ab",
                      "type": "string"
                    },
                    "population": {
                      "description": "Survey population size (optional, for finite correction)",
                      "type": "number"
                    },
                    "power": {
                      "description": "A/B power 0.5 to 0.99 (default 0.8)",
                      "type": "number"
                    },
                    "proportion": {
                      "description": "Expected proportion for a survey (default 0.5)",
                      "type": "number"
                    },
                    "target": {
                      "description": "A/B rate you want to detect, e.g. 0.12",
                      "type": "number"
                    }
                  },
                  "required": [
                    "mode"
                  ],
                  "type": "object"
                },
                "type": {
                  "const": "http",
                  "type": "string"
                }
              },
              "required": [
                "type",
                "method"
              ],
              "type": "object"
            },
            "output": {
              "properties": {
                "example": {
                  "properties": {
                    "asOf": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "confidence": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "degraded": {
                      "type": [
                        "boolean",
                        "null"
                      ]
                    },
                    "disclaimer": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "finitePopulationApplied": {
                      "type": [
                        "boolean",
                        "null"
                      ]
                    },
                    "margin": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "notChecked": {
                      "items": {
                        "type": "string"
                      },
                      "type": [
                        "array",
                        "null"
                      ]
                    },
                    "proportion": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "reasons": {
                      "items": {
                        "type": "string"
                      },
                      "type": [
                        "array",
                        "null"
                      ]
                    },
                    "required": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "source": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "summary": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "unroundedInfinitePopulation": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "verdict": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "z": {
                      "type": [
                        "null",
                        "number"
                      ]
                    }
                  },
                  "type": "object"
                },
                "type": {
                  "type": "string"
                }
              },
              "required": [
                "type"
              ],
              "type": "object"
            }
          },
          "required": [
            "input"
          ],
          "type": "object"
        }
      }
    },
    "lastUpdated": "2026-11-01T23:38:08.033Z",
    "quality": {
      "l30DaysTotalCalls": 2,
      "l30DaysUniquePayers": 2,
      "lastCalledAt": "2026-11-01T23:38:07.88Z"
    },
    "resource": "https://math-stats.x402tookit.com/sample-size",
    "serviceName": "Math and Statistics",
    "tags": [
      "statistics",
      "sample-size",
      "power",
      "survey",
      "ab-test"
    ],
    "type": "http",
    "x402Version": 2
  },
  "source": "x402_bazaar",
  "summary": "Required sample size for a survey (margin of error, optional finite population) or an A/B test (baseline, lift, power)."
}

What the leaf hashes

{"body":"ef87751c550266b149ccd98f25c444833fed7188fd30ce257be4a8f751e8db62","id":2201577,"kind":"listing","method":"sync.x402_bazaar/1","observed_us":1793646806750994,"prev":null,"subject":"x402_bazaar:https://math-stats.x402tookit.com/sample-size","subject_kind":"source_record"}

Proof

Fold these into the leaf in order, hashing each sorted pair with keccak256, to reach the root of 2026-11-02 (444186 rows).

1. 0xf7ccde94056061bdf9f25f105e1edbc86b97254142c517c90fa19c15b81cdbea
2. 0x67cb4c57d830716828230cda7711df0707454afaa65074b91bc46e9cd2d03f7b
3. 0x758ffee6443b319900fc5186ab4d7bf901293312112f1e318100923d87f94d05
4. 0x2e64572a4b5ba9b4d612f4caf0bf31f2a99b3522c57d683ba2df3635605858c4
5. 0x23c84b323ca82b75366cd1a09dd564dfb03150cfc778520934ecead270fc55a9
6. 0x84425b11509645cbb2ef86644b370586f56699272d84d82d827f988803550068
7. 0x619c6122707379f881793613a3c4b21af48dba4e075e70b9c6c6ccccd9c073f2
8. 0x779e8d7080fe56fe7ef192acde4fdf224455fc76338c0e3595d200da4e3a286d
9. 0x417a5f53b3ea1ec534eb34a3dacfe971280f9a9dc1399a9c9a3e3c8b7eb8fe69
10. 0xe4c724accb96e775b19f59aea04de926583bbcb28d919ef872a1cad6bdb265f8
11. 0xe1e485a8d27668a5976b2d5832055d1e4425c667e5808932fbd2c3f56f9ddc1f
12. 0x93c9b5204cb75374db0fc8940c7bb2dfc4f17b307130f5a55adb819570fd792c
13. 0x54a66ecba86fe13527453978f73a6a3d80e1817889872b25f2a79c90d4b86982
14. 0x70f4b5a4c6a4de9977aecf5fbe7497e271e9e2f9e5068c7dad5953e8fe898b30
15. 0x4068a4306db47ea0eae5f76e5137753caa3dbb132dca6a61a4d6c1838a52700f
16. 0x25127db2e775737b2874f6a159f7c1bf984317eea6482e94589c3ef4c5ccab32
17. 0xec5d643575d83c9e07e65deeef71943b53cbf3007e7e2b9a6ef414081509b0cc
18. 0x252cce55f1a3d5391c16f82d7f62494429a5f69b03486d4cfcfb7b2c96d6c884

Day root

0x78fecaabbe319e56f5c4b80fc02e2052e198ad24781da8832a475ff65f2002d1

Chained

0xdc35957db5d1371ca382b9152878ffece28ec7c5cb4f98fd71ddb367f8b999b2

Published

On Arc Testnet, block 70432815: 0x56b814612eb2e3e544153df3e91e1f7199106d1e430c7d8c6b653feeb9ebe9af