{ "category": "Compatibility", "display_name": "CHIDIST", "entry_kind": "built_in_function", "eval_api": { "method": "POST", "url": "https://handbook.dnacalc.com/api/eval" }, "function_id": "FUNC.CHIDIST", "implementation_state": { "answer_bank": { "excel_builds": [ "20131", "?" ], "larger_numeric": 1, "last_bit": 137, "matched": 250, "other_mismatch": 0, "refused": 0, "rows": 388, "unread": 0, "worst_ulp": 24 }, "detail": "Of 392 recorded answers (388 in the answer bank and 4 workbook cells), 140 do not match: 1 differ by more than 16 ULP, 139 differ by at most 16 ULP.", "dnacalc_commit": "9e1884369a678158dd82d3d74188daf986995e87", "in_catalogue": true, "state": "differs", "state_label": "Known larger differences", "summary": "Known larger differences on 140 of 392 recorded answers", "workbook_corpus": { "cells": 4, "last_bit": 2, "matched": 2, "worst_ulp": 2 } }, "implementations": [ { "commit": "9e1884369a678158dd82d3d74188daf986995e87", "flavour": "excel-compatibility-candidate", "language": "Rust", "name": "CalcFunc", "own_code": [ "https://github.com/DnaCalc/DnaCalc/blob/9e1884369a678158dd82d3d74188daf986995e87/crates/calc-func/src/catalogue/distributions.rs#L120-L123" ], "repository": "https://github.com/DnaCalc/DnaCalc", "shared_code": [ "catalogue/distributions::nums", "ported/chi_f_t_family::truncate_positive_integer", "ported/chi_f_t_family::validate_nonnegative_x", "ported/chi_f_t_family::chisq_dist_rt_kernel", "ported/excel_numeric::binary_with", "ported/excel_numeric::excel_expm1_internal", "ported/excel_numeric::expm1_internal_graph", "ported/excel_numeric::excel_x87_add", "ported/excel_numeric::excel_x87_sub", "ported/excel_numeric::excel_x87_mul", "ported/excel_numeric::excel_x87_temme_finish", "ported/excel_numeric::excel_x87_div", "ported/excel_numeric/x87::mul", "ported/excel_numeric/x87::add", "ported/excel_numeric/x87::sub", "ported/excel_numeric/x87::div", "ported/excel_numeric/x87_chains::pow2_positive", "ported/excel_numeric/x87_chains::pow2", "ported/excel_numeric/x87_chains::exp_ext", "ported/excel_numeric/x87_chains::exp_with", "ported/excel_numeric/x87_chains::excel_exp", "ported/excel_numeric/x87_chains::log_with", "ported/excel_numeric/x87_chains::excel_log", "ported/normal_dist_common::stored_horner", "ported/normal_dist_common::erf_approx", "ported/normal_dist_common::erfc_upper", "ported/special_dist_family::erfc_of_sqrt_half_x", "ported/special_dist_family::erfc_kernel", "ported/special_dist_family::erfc_precise_kernel", "ported/special_math_common::gratio_norm_gamma", "ported/special_math_common::gratio_rexp", "ported/special_math_common::gratio_rlog", "ported/special_math_common::gratio_gam1", "ported/special_math_common::gratio", "ported/special_math_common::series_prefactor", "ported/special_math_common::gratio_after40", "ported/special_math_common::gratio_cf", "ported/special_math_common::gratio_temme_270", "ported/special_math_common::gratio_temme_340", "ported/special_math_common::gratio_temme_330", "ported/special_math_common::gratio_temme_finish", "ported/special_math_common::regularized_gamma_q" ], "source": "https://github.com/DnaCalc/DnaCalc/blob/9e1884369a678158dd82d3d74188daf986995e87/crates/calc-func/src/catalogue/distributions.rs#L120-L123", "state": "differs", "suite": null, "summary": "Known larger differences on 140 of 392 recorded answers" } ], "json_url": "https://handbook.dnacalc.com/api/functions/FUNC.CHIDIST.json", "name": "CHIDIST", "notes": [], "schema": "efh.function-reference/v1", "section_order": [ "what-it-does", "try-it", "quirks", "how-to-implement", "version-differences", "alternatives" ], "sections": { "alternatives": "\n[CHISQ.INV.RT](FUNC.CHISQ.INV.RT.md) inverts the corresponding probability. [CHISQ.TEST](FUNC.CHISQ.TEST.md) computes a test probability from observed and expected counts.\n\n\n", "how-to-implement": "\nFor df=1 the current route calls ERFC.PRECISE at `sqrt(x/2)`, preserving divide-then-square-root order. For df=2 it calls the measured public EXP at `-(x/2)`. Otherwise evaluate the regularized upper gamma ratio `Q(df/2,x/2)` directly. Avoid obtaining a tiny tail by subtracting a near-one CDF. The worked df=2 value follows from `x/2=1`. The numerical outline is an implementation route, not an identification of every Excel approximation or return-rounding stage. The current problem-functions report retains unresolved distribution mismatches.\n\n\n", "quirks": "\nDegrees of freedom are truncated. Negative x and an admitted degree count below one or above `10^10` give `#NUM!` in the current shared family. Nonnumeric arguments give `#VALUE!`. A right tail is not a density.\n\n\n", "sources": "\n- [Microsoft: CHIDIST function](https://support.microsoft.com/en-us/excel/functions/chidist-function), opened 6 November 2026; syntax, documented argument rules and errors.\n- [DnaCalc implementation](https://github.com/DnaCalc/DnaCalc/blob/da3ecc4fb19a3a5529708c311d0e8f05688ac165/crates/calc-func/src/ported/chi_f_t_family.rs); implementation steps and the limits identified in the text.\n\n", "try-it": "\n`=CHIDIST(2,2)` is about `0.367879441171442`. At two degrees of freedom the right tail is `exp(-x/2)`. The tail at x=0 is one.\n\n\n", "version-differences": "The recorded environments below distinguish a reading from a same-input comparison. Counts describe captured inputs in each environment; overlapping captures and comparisons are not totals of unique worksheet calls.\n\n| Excel 16.0 build | Platform and CPU | Captured inputs |\n|---|---|---:|\n| 19929 | Windows, bitness not recorded, CPU not recorded | 41 |\n| 20131 | Windows, bitness not recorded, AMD Ryzen 7 4800H with Radeon Graphics | 388 |\n\n- XC-CHIDIST-001: build 19929 versus build 20131; 10 same-input pairs, 0 differing answers. Compared axes: excel-build. Numeric answers were compared by their recorded binary64 bits; other answers by typed value.\n\nAgreement on these compared inputs does not establish agreement on unmeasured inputs.\n\n[Recorded environments and comparison details](https://github.com/DnaCalc/ExcelFunctionsHandbook/blob/5dc75391aa5125ccc5abdb095da85950980d6fd8/content/evidence/environments/FUNC.CHIDIST.json).", "what-it-does": "\n`CHIDIST(x, deg_freedom)` returns the chi-square probability to the right of x. CHIDIST is the compatibility name for the right tail.\n\n\n" }, "signature": { "display": "CHIDIST(x, deg_freedom)", "parameters": [ { "description": null, "name": "x", "optional": false, "repeats": false }, { "description": null, "name": "deg_freedom", "optional": false, "repeats": false } ], "trailing_repeats": false }, "sources": { "metadata": { "admission": { "label": "implemented", "reason": null }, "arity": { "max": 2, "min": 2 }, "category": "Compatibility", "classification": { "arg_preparation_profile": "ValuesOnlyPreAdapter", "coercion_lift_profile": "Custom", "determinism_class": "Deterministic", "error_collapse_profile": "None", "fec_dependency_profile": "None", "host_interaction_class": "None", "kernel_signature_class": "Custom", "rich_value_usage": "RichBlind", "surface_fec_dependency_profile": "RefOnly", "thread_safety_class": "SafePure", "volatility_class": "NonVolatile" }, "descriptions": { "long": null, "short": "Right-tail probability of the chi-squared distribution (older form)", "short_source": "dna-calc-own" }, "docs": { "english_description": "Returns the one-tailed probability of the chi-squared distribution", "microsoft_url": "https://support.microsoft.com/en-us/office/chidist-function-c90d0fbc-5b56-4f5f-ab57-34af1bf6897e" }, "entry_kind": "built_in_function", "localized_family_names": null, "localized_names": [ { "locale": "ar-SA", "name": "CHIDIST" }, { "locale": "bg-BG", "name": "CHIDIST" }, { "locale": "cs-CZ", "name": "CHIDIST" }, { "locale": "da-DK", "name": "CHIFORDELING" }, { "locale": "de-DE", "name": "CHIDIST" }, { "locale": "el-GR", "name": "CHIDIST" }, { "locale": "en-AU", "name": "CHIDIST" }, { "locale": "en-GB", "name": "CHIDIST" }, { "locale": "en-US", "name": "CHIDIST" }, { "locale": "es-ES", "name": "DISTR.CHI" }, { "locale": "et-EE", "name": "CHIDIST" }, { "locale": "fi-FI", "name": "CHIJAKAUMA" }, { "locale": "fr-FR", "name": "LOI.KHIDEUX*" }, { "locale": "he-IL", "name": "CHIDIST" }, { "locale": "hr-HR", "name": "CHIDIST" }, { "locale": "hu-HU", "name": "KHI.ELOSZLÁS" }, { "locale": "id-ID", "name": "CHIDIST" }, { "locale": "it-IT", "name": "CHIDIST" }, { "locale": "ja-JP", "name": "CHIDIST" }, { "locale": "ko-KR", "name": "CHIDIST" }, { "locale": "lt-LT", "name": "CHIDIST" }, { "locale": "lv-LV", "name": "CHIDIST" }, { "locale": "nb-NO", "name": "KJI.FORDELING" }, { "locale": "nl-NL", "name": "CHI.KWADRAAT" }, { "locale": "pl-PL", "name": "ROZKŁAD.CHI" }, { "locale": "pt-BR", "name": "QUIDIST" }, { "locale": "pt-PT", "name": "DIST.CHI" }, { "locale": "ro-RO", "name": "CHIDIST" }, { "locale": "ru-RU", "name": "ХИ2РАСП" }, { "locale": "sk-SK", "name": "CHIDIST" }, { "locale": "sl-SI", "name": "CHIDIST" }, { "locale": "sr-Latn-RS", "name": "CHIDIST" }, { "locale": "sv-SE", "name": "CHI2FÖRD" }, { "locale": "th-TH", "name": "CHIDIST" }, { "locale": "tr-TR", "name": "KİKAREDAĞ işlevi" }, { "locale": "uk-UA", "name": "CHIDIST" }, { "locale": "vi-VN", "name": "CHIDIST" }, { "locale": "zh-CN", "name": "CHIDIST" }, { "locale": "zh-HK", "name": "CHIDIST" }, { "locale": "zh-TW", "name": "CHIDIST" } ], "signature": { "display": "CHIDIST(x, deg_freedom)", "parameters": [ { "description": null, "name": "x", "optional": false, "repeats": false }, { "description": null, "name": "deg_freedom", "optional": false, "repeats": false } ], "trailing_repeats": false }, "surface_name": "CHIDIST", "version_marker": null, "xlcall": { "code": "274", "symbol": "xlfChidist" } }, "microsoft": "https://support.microsoft.com/en-us/office/chidist-function-c90d0fbc-5b56-4f5f-ab57-34af1bf6897e" }, "try_it": { "formula": "=CHIDIST(2,2)" }, "url": "https://handbook.dnacalc.com/functions/CHIDIST.html", "variants": [], "versions": [ { "behaviour": "41 captured inputs are indexed for this environment. Capture dates are not recorded. This is a reading count, not a comparison with another build.", "excel_build": "16.0 build 19929", "platform": "Windows, bitness not recorded, CPU not recorded", "sources": [ "https://github.com/DnaCalc/ExcelFunctionsHandbook/blob/5dc75391aa5125ccc5abdb095da85950980d6fd8/content/evidence/environments/FUNC.CHIDIST.json" ] }, { "behaviour": "388 captured inputs are indexed for this environment. Capture dates: 2026-07-12 to 2026-07-17. This is a reading count, not a comparison with another build.", "excel_build": "16.0 build 20131", "platform": "Windows, bitness not recorded, AMD Ryzen 7 4800H with Radeon Graphics", "sources": [ "https://github.com/DnaCalc/ExcelFunctionsHandbook/blob/5dc75391aa5125ccc5abdb095da85950980d6fd8/content/evidence/environments/FUNC.CHIDIST.json" ] } ] }