{ "category": "Compatibility", "display_name": "FTEST", "entry_kind": "built_in_function", "eval_api": { "method": "POST", "url": "https://handbook.dnacalc.com/api/eval" }, "function_id": "FUNC.FTEST", "implementation_state": { "answer_bank": null, "detail": "Recorded: 6 workbook cells.", "dnacalc_commit": "9e1884369a678158dd82d3d74188daf986995e87", "in_catalogue": true, "state": "matches", "state_label": "Matches every recorded Excel answer", "summary": "Matches all 6 recorded answers", "workbook_corpus": { "cells": 6, "matched": 6 } }, "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#L337-L341" ], "repository": "https://github.com/DnaCalc/DnaCalc", "shared_code": [ "catalogue/distributions::sample", "ported/chi_f_t_family::truncate_positive_integer", "ported/chi_f_t_family::validate_nonnegative_x", "ported/chi_f_t_family::f_dist_rt_kernel", "ported/excel_numeric::binary_with", "ported/excel_numeric::excel_x87_add", "ported/excel_numeric::excel_x87_mul", "ported/excel_numeric::excel_x87_mul_add", "ported/excel_numeric/x87::mul", "ported/excel_numeric/x87::add", "ported/special_math_common::bratio_ftoi", "ported/special_math_common::bratio_spmpar1", "ported/special_math_common::bratio_exparg", "ported/special_math_common::bratio_esum", "ported/special_math_common::bratio_esum20", "ported/special_math_common::bratio_alnrel", "ported/special_math_common::bratio_rlog1", "ported/special_math_common::bratio_gam1", "ported/special_math_common::bratio_gamln1", "ported/special_math_common::bratio_gamln", "ported/special_math_common::bratio_algdiv", "ported/special_math_common::bratio_bcorr", "ported/special_math_common::bratio_gsumln", "ported/special_math_common::bratio_betaln", "ported/special_math_common::bratio_betaln_60", "ported/special_math_common::bratio_erf_nswc", "ported/special_math_common::bratio_erfc1", "ported/special_math_common::bratio_rexp", "ported/special_math_common::bratio_psi", "ported/special_math_common::bratio_fpser", "ported/special_math_common::bratio_apser", "ported/special_math_common::bratio_bpser", "ported/special_math_common::bratio_bup", "ported/special_math_common::bratio_brcomp", "ported/special_math_common::bratio_brcmp1", "ported/special_math_common::bratio_bfrac", "ported/special_math_common::bratio_bgrat", "ported/special_math_common::bratio_grat1", "ported/special_math_common::bratio_basym", "ported/special_math_common::bratio", "ported/statistical_tests_family::sample_mean", "ported/statistical_tests_family::sample_variance", "ported/statistical_tests_family::f_test_kernel" ], "source": "https://github.com/DnaCalc/DnaCalc/blob/9e1884369a678158dd82d3d74188daf986995e87/crates/calc-func/src/catalogue/distributions.rs#L337-L341", "state": "matches", "suite": null, "summary": "Matches all 6 recorded answers" } ], "json_url": "https://handbook.dnacalc.com/api/functions/FUNC.FTEST.json", "name": "FTEST", "notes": [], "schema": "efh.function-reference/v1", "section_order": [ "what-it-does", "try-it", "quirks", "how-to-implement", "version-differences", "alternatives" ], "sections": { "alternatives": "\n[F.DIST.RT](FUNC.F.DIST.RT.md) accepts a supplied ratio; [VAR.S](FUNC.VAR.S.md) reports sample variance; [T.TEST](FUNC.T.TEST.md) compares means under its selected model.\n\n\n", "how-to-implement": "\nCompute each sample variance and its count, put the larger variance in the numerator, and retain its matching degree count `n-1`. Evaluate the F right tail of the ratio, double it and cap at one. For the example both variances are one and both degree counts two. The current helper uses its own centered binary64 sample-variance calculation; it does not automatically inherit the separately recovered VAR.S computation tree. Tail and reduction discrepancies remain recorded.\n\n\n", "quirks": "\nEach sample needs at least two numeric observations and a nonzero variance, otherwise `#DIV/0!`. Text, logical values and blanks in references are ignored; zeros count. Equal sample variances do not imply equal sample means or identical observations.\n\n\n", "sources": "\n- [Microsoft: FTEST function](https://support.microsoft.com/en-us/excel/functions/ftest-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/statistical_tests_family.rs); implementation steps and the limits identified in the text.\n\n", "try-it": "\n`=FTEST({1,2,3},{2,3,4})` returns `1` under the current route. Both sample variances are one, so their ratio is one with equal degree counts.\n\n\n", "version-differences": "\nNo same-input comparison between named Excel builds is recorded for this function here. The documented behaviour below is not a measurement of every Excel release.\n\n\n", "what-it-does": "\n`FTEST(array1,array2)` returns a two-tailed F-test probability for comparing sample variances. FTEST is the compatibility spelling. It returns a probability, rather than the variance ratio statistic.\n\n\n" }, "signature": { "display": "FTEST(array1, array2)", "parameters": [ { "description": null, "name": "array1", "optional": false, "repeats": false }, { "description": null, "name": "array2", "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": "RefsVisibleInAdapter", "coercion_lift_profile": "Custom", "determinism_class": "Deterministic", "error_collapse_profile": "None", "fec_dependency_profile": "RefOnly", "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": "Two-tailed F-test probability (older form of F.TEST)", "short_source": "dna-calc-own" }, "docs": { "english_description": "Returns the result of an F-test", "microsoft_url": "https://support.microsoft.com/en-us/office/ftest-function-4c9e1202-53fe-428c-a737-976f6fc3f9fd" }, "entry_kind": "built_in_function", "localized_family_names": null, "localized_names": [ { "locale": "ar-SA", "name": "FTEST" }, { "locale": "bg-BG", "name": "FTEST" }, { "locale": "cs-CZ", "name": "FTEST" }, { "locale": "da-DK", "name": "FTEST" }, { "locale": "de-DE", "name": "FTEST" }, { "locale": "el-GR", "name": "FTEST" }, { "locale": "en-AU", "name": "FTEST" }, { "locale": "en-GB", "name": "FTEST" }, { "locale": "en-US", "name": "FTEST" }, { "locale": "es-ES", "name": "PRUEBA.F" }, { "locale": "et-EE", "name": "FTEST" }, { "locale": "fi-FI", "name": "FTESTI" }, { "locale": "fr-FR", "name": "TEST.F*" }, { "locale": "he-IL", "name": "FTEST" }, { "locale": "hr-HR", "name": "FTEST" }, { "locale": "hu-HU", "name": "F.PRÓBA" }, { "locale": "id-ID", "name": "FTEST" }, { "locale": "it-IT", "name": "FTEST" }, { "locale": "ja-JP", "name": "FTEST" }, { "locale": "ko-KR", "name": "FTEST" }, { "locale": "lt-LT", "name": "FTEST" }, { "locale": "lv-LV", "name": "FTEST" }, { "locale": "nb-NO", "name": "FTEST" }, { "locale": "nl-NL", "name": "F.TOETS" }, { "locale": "pl-PL", "name": "TEST.F" }, { "locale": "pt-BR", "name": "FTEST" }, { "locale": "pt-PT", "name": "TESTEF" }, { "locale": "ro-RO", "name": "FTEST" }, { "locale": "ru-RU", "name": "ФТЕСТ" }, { "locale": "sk-SK", "name": "FTEST" }, { "locale": "sl-SI", "name": "FTEST" }, { "locale": "sr-Latn-RS", "name": "FTEST" }, { "locale": "sv-SE", "name": "FTEST" }, { "locale": "th-TH", "name": "FTEST" }, { "locale": "tr-TR", "name": "FTEST işlevi" }, { "locale": "uk-UA", "name": "FTEST" }, { "locale": "vi-VN", "name": "FTEST" }, { "locale": "zh-CN", "name": "FTEST" }, { "locale": "zh-HK", "name": "FTEST" }, { "locale": "zh-TW", "name": "FTEST" } ], "signature": { "display": "FTEST(array1, array2)", "parameters": [ { "description": null, "name": "array1", "optional": false, "repeats": false }, { "description": null, "name": "array2", "optional": false, "repeats": false } ], "trailing_repeats": false }, "surface_name": "FTEST", "version_marker": null, "xlcall": { "code": "310", "symbol": "xlfFtest" } }, "microsoft": "https://support.microsoft.com/en-us/office/ftest-function-4c9e1202-53fe-428c-a737-976f6fc3f9fd" }, "try_it": { "formula": "=FTEST({1,2,3},{2,3,4})" }, "url": "https://handbook.dnacalc.com/functions/FTEST.html", "variants": [], "versions": [] }