{"uid":"cap_7GzKZdvdOGnLm28oPMjvo","slug":"delx-standard-deviation-0baa7a87","name":"Delx Standard Deviation","description":"Standard deviation. Call for simple volatility or spread checks on agent-collected samples. Returns population/sample stdev fields depending on input flags. $0.001 USDC per successful call via x402 on Base—deterministic first-party JSON, no API key, no subscription, and nothing is billed on structured validation errors.","url":"https://api.delx.ai/api/v1/x402/stdev","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"sample":{"description":"Optional sample input."},"values":{"type":"array","items":{"type":"number"},"maxItems":10000,"minItems":1,"description":"Numeric samples for stats tools (mean/median/stdev/percentile). Cap 10k numbers."}}},"responseSchema":{"type":"json","example":{"mean":6,"mode":"population","count":5,"stdev":2.82842712474619,"schema":"delx/stdev/v1"}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_IS5xLo6vmqpB1yPPlLpiu","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes population and/or sample standard deviation for a list of numeric values","exampleAgentPrompt":"Can you calculate the standard deviation of these sensor readings for me: [12.4, 13.1, 11.9, 14.2, 12.8, 13.5, 11.7] — I need both population and sample stdev.","exampleUseCases":[{"title":"Volatility check on price samples","prompt":"I collected 20 price samples from different vendors — [4.50, 4.75, 5.10, 4.90, 5.20, 4.65, 4.80, 5.00, 4.70, 4.95, 5.15, 4.60, 4.85, 5.05, 4.55, 4.78, 5.08, 4.68, 4.92, 5.25] — can you compute the standard deviation so I can see how volatile pricing is across suppliers?"},{"title":"Quality control spread on measurements","prompt":"I have a batch of 15 part measurements in millimeters: [10.01, 9.99, 10.02, 10.00, 9.98, 10.03, 9.97, 10.01, 10.00, 9.99, 10.02, 9.98, 10.01, 10.00, 9.99] — what's the sample standard deviation to check if they're within tolerance?"},{"title":"Score dispersion in agent survey results","prompt":"My agent gathered these response scores from 12 users: [7, 8, 6, 9, 7, 8, 5, 9, 8, 7, 6, 8] — calculate the standard deviation to see how consistent the feedback was."}],"resultDescription":"Returns a JSON object containing population standard deviation and/or sample standard deviation fields computed from the supplied numeric array, depending on input flags provided.","failureModes":["Empty or missing values array returns a structured validation error (not billed)","Non-numeric items in the array cause a validation error","Array exceeding 10,000 items is rejected","Payment failure or insufficient USDC balance on Base results in 402 error","Malformed JSON body returns a validation error (not billed)"],"whenToPreferThis":"Choose this endpoint when an agent needs a deterministic, pay-per-call standard deviation computation without managing an API key or subscription. Ideal for lightweight statistical checks on agent-collected numeric samples — especially volatility or spread checks in automated pipelines where reproducibility matters and billing only occurs on successful calls.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T19:02:30.887Z","isFirstParty":false}