Calculate Population Variance

statistics.population_variance

ProductionBounded custom (Class B)Deterministicstrictinstantv1.0.0

No network

Overview

Calculate bounded exact-decimal population variance with an explicit denominator and audit trace. Observation order is preserved, null and non-decimal members are rejected, and no missing-value or business policy is inferred.

You receive the exact formula result, denominator, bounds, and trace fields needed to reproduce population variance.

Reliability

Exact BigDecimal accumulation uses a fixed 100-digit HALF_EVEN context. DECIMAL_INVALID means a malformed or over-limit decimal; correct that value. SERIES_INVALID means too few observations; add the required observations. LENGTH_MISMATCH means x and y counts differ; align the paired rows. ZERO_VARIANCE means Pearson correlation has a constant series; provide varying observations. ITEM_LIMIT_EXCEEDED means more than 10,000 observations; split them. This guidance applies specifically to statistics.population_variance.

Context footprint

One bounded request replaces repeated prompt arithmetic and returns its denominator trace. This guidance applies specifically to statistics.population_variance. A successful call costs 1 execution credit.

When to use it

Use when one decimal series needs population variance with denominator n.

When you want sample variance (n-1) or the standard deviation instead of population variance.

Scope

Note

Calculate bounded exact-decimal population variance with an explicit denominator and audit trace

Non-goals

Does not infer sampling, missing-value, weighting, unit, or materiality policy This guidance applies specifically to statistics.population_variance.
Does not accept binary floating point, null observations, files, or unbounded series This guidance applies specifically to statistics.population_variance.

Properties

IdempotentRetry safeStreaming supportedFile input supportedRequires external service

Capabilities

analysismath

Cost & billing

Flat rate per invocation

MetercallsBillable onsuccessCost per call1 credit

File handling

Accepts file_refProduces file_refMax input64 KB

How we handle your data

Sensitive input, safe output

What this means

This skill may receive sensitive content, but it does not target sensitive data and returns only a structured non-sensitive result.

Squillify guarantees

Runs inside Squillify
This skill runs inside Squillify.
Payloads are not sent to an external service by this skill.
Squillify does not permanently store submitted payloads.
Telemetry records metadata only, not submitted content.
Submitted payloads are not used for training.
Submitted payloads are not reviewed by humans.
This skill does not target sensitive data.
The response does not contain submitted content.

Your responsibility

Squillify does not determine whether submitted content is sensitive. Your application is responsible for deciding what data it is allowed to submit. Your application is responsible for securing the response.

Read the Microskill Data Handling Policy

Input schema

Field	Type	Required	Description
values	array	Yes	Required 1 to 10,000 plain-decimal strings; sample variance requires at least 2.

Output schema

Field	Type	Required	Description
variance	string	Yes	Variance under the declared n or n-1 denominator.
mean	string	Yes	Arithmetic mean used for centered differences.
count	integer	Yes	Number of observations.
denominator	string	Yes	Exactly n for population or n-1 for sample.

API contract

POST /v1/execute

curl

curl -sS -X POST "$BASE/v1/execute" -H "Authorization: Bearer $KEY" -H 'Content-Type: application/json' -d '{"skillKey":"statistics.population_variance","input":{"values":["2","4","6"]}}'

Integrations

TypeScript SDK

import { Squillify } from "@squillify/sdk";

const sq = new Squillify({ apiKey: process.env.SQUILLIFY_API_KEY });

const { output } = await sq.execute("statistics.population_variance", {"values":["2","4","6"]});

Errors

Code	HTTP	Retryable	Description
VALIDATION_ERROR	400	No	The request payload failed schema validation.
UNAUTHORIZED	401	No	Missing or invalid API key.
SKILL_NOT_ACCESSIBLE	403	No	The API key is not granted access to this skill.
SKILL_NOT_AVAILABLE_FOR_PLAN	403	No	This skill is not included in your current plan.
PLAN_ELIGIBILITY_UNAVAILABLE	503	Yes	Plan eligibility could not be decided. Retry after backoff.
SKILL_NOT_FOUND	404	No	The requested skill or version does not exist.
TENANT_RATE_LIMITED	429	Yes	Request rate limit exceeded. Retry after backoff.
QUOTA_EXCEEDED	429	Yes	Plan quota exhausted. Retryable once the quota period resets.
EXECUTION_TIMEOUT	504	Yes	Execution exceeded the allowed time budget.
DECIMAL_INVALID	400	No	The request payload failed this skill's input validation.
SERIES_INVALID	400	No	The request payload failed this skill's input validation.
ITEM_LIMIT_EXCEEDED	429	No	A size, quota, rate, or time limit was exceeded.

Other limits

Limit	Value
Recommended inline bytes	32 KiB

Limitations

Does not infer sampling, missing-value, weighting, unit, or materiality policy This guidance applies specifically to statistics.population_variance.
Does not accept binary floating point, null observations, files, or unbounded series This guidance applies specifically to statistics.population_variance.
Datasets requiring missing-value imputation or statistical inference
Inputs above 10,000 observations or requiring streaming This guidance applies specifically to statistics.population_variance.

How to call

POST /v1/execute (requires authentication)

Request bodyjson

{
  "skillKey": "statistics.population_variance",
  "input": {
    "values": [
      "2",
      "4",
      "6"
    ]
  }
}

Examples

Primary decimal series

Inputjson

{
  "values": [
    "2",
    "4",
    "6"
  ]
}

Expected outputjson

{
  "mean": "4",
  "denominator": "n",
  "count": 3,
  "variance": "2.666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666667"
}

Signed or alternative denominator series