{ "category": "Compatibility", "display_name": "ZTEST", "entry_kind": "built_in_function", "eval_api": { "method": "POST", "url": "https://handbook.dnacalc.com/api/eval" }, "function_id": "FUNC.ZTEST", "implementation_state": { "answer_bank": null, "detail": "Everything else matches (7 workbook cells). Last-bit means a finite number within 16 ULP of Excel's.", "dnacalc_commit": "9e1884369a678158dd82d3d74188daf986995e87", "in_catalogue": true, "state": "close", "state_label": "Close: last-bit deviations remain", "summary": "Close: 4 of 7 recorded answers differ in the last bits, worst 3 ULP", "workbook_corpus": { "cells": 7, "last_bit": 4, "matched": 3, "worst_ulp": 3 } }, "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#L349-L349" ], "repository": "https://github.com/DnaCalc/DnaCalc", "shared_code": [ "catalogue/distributions::sample", "catalogue/distributions::z_test_of", "ported/confidence_test_family::z_test_kernel", "ported/excel_numeric::binary_with", "ported/excel_numeric::excel_x87_add", "ported/excel_numeric::excel_x87_sub", "ported/excel_numeric::excel_x87_mul", "ported/excel_numeric::excel_x87_div", "ported/excel_numeric::excel_sqrt_staged", "ported/excel_numeric/x87::mul", "ported/excel_numeric/x87::add", "ported/excel_numeric/x87::sub", "ported/excel_numeric/x87::div", "ported/normal_dist_common::stored_horner", "ported/normal_dist_common::erf_approx", "ported/normal_dist_common::erfc_upper", "ported/normal_log_family::flush_subnormal", "ported/normal_log_family::identified_std_normal_cdf", "ported/normal_log_family::norm_cdf", "ported/normal_log_family::norm_s_dist_kernel", "ported/phi_fn::phi_kernel", "ported/special_dist_family::erfc_kernel", "ported/special_dist_family::erfc_precise_kernel", "ported/variance_common::variance_from_values", "ported/variance_common::stdev_from_values" ], "source": "https://github.com/DnaCalc/DnaCalc/blob/9e1884369a678158dd82d3d74188daf986995e87/crates/calc-func/src/catalogue/distributions.rs#L349-L349", "state": "close", "suite": null, "summary": "Close: 4 of 7 recorded answers differ in the last bits, worst 3 ULP" } ], "json_url": "https://handbook.dnacalc.com/api/functions/FUNC.ZTEST.json", "name": "ZTEST", "notes": [], "schema": "efh.function-reference/v1", "section_order": [ "what-it-does", "try-it", "quirks", "how-to-implement", "version-differences", "alternatives" ], "sections": { "alternatives": "\n[Z.TEST](FUNC.Z.TEST.md) is the modern spelling; [T.TEST](FUNC.T.TEST.md) supplies a t-based comparison; [NORM.S.DIST](FUNC.NORM.S.DIST.md) evaluates a normal CDF directly.\n\n\n", "how-to-implement": "\nCompute the numeric count and mean. If sigma is omitted, obtain sample standard deviation from the recovered variance family. The recorded current combination is `z=(x-mean)*sqrt(n)/sigma`, then the standard-normal **left CDF** at z. Do not rewrite it as a right-tail subtraction on `(mean-x)/(sigma/sqrt(n))`: mathematically equivalent forms have different stored results. The equal-mean example gives z=0 and probability one half. Inner normal tails still depend on the open ERFC factor.\n\n\n", "quirks": "\nThe public page documents `#N/A` for an empty array. The current helper has its own empty/nonfinite validation, so retain that error distinction in comparisons. A supplied scale must be positive, and an omitted scale needs enough sample data. A two-tailed test uses `2*MIN(p,1-p)` under the stated worksheet composition, not simply `2*p` in every case.\n\n\n", "sources": "\n- [Microsoft: ZTEST function](https://support.microsoft.com/en-us/excel/functions/ztest-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/confidence_test_family.rs); implementation steps and the limits identified in the text.\n\n", "try-it": "\n`=ZTEST({1,2,3},2,1)` returns `0.5`: the sample mean equals the hypothesis. If the sample mean exceeds x, this one-tail result is below one half.\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`ZTEST(array,x,[sigma])` returns a one-tailed normal-test probability for a hypothesised population mean x. Supply a known population standard deviation sigma, or let the function use sample standard deviation. This is the compatibility name.\n\n\n" }, "signature": { "display": "ZTEST(array, x, [sigma])", "parameters": [ { "description": null, "name": "array", "optional": false, "repeats": false }, { "description": null, "name": "x", "optional": false, "repeats": false }, { "description": null, "name": "sigma", "optional": true, "repeats": false } ], "trailing_repeats": false }, "sources": { "metadata": { "admission": { "label": "implemented", "reason": null }, "arity": { "max": 3, "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": "One-tailed z-test probability (older form of Z.TEST)", "short_source": "dna-calc-own" }, "docs": { "english_description": "Returns the one-tailed probability-value of a z-test", "microsoft_url": "https://support.microsoft.com/en-us/office/ztest-function-8f33be8a-6bd6-4ecc-8e3a-d9a4420c4a6a" }, "entry_kind": "built_in_function", "localized_family_names": null, "localized_names": [ { "locale": "ar-SA", "name": "ZTEST" }, { "locale": "bg-BG", "name": "ZTEST" }, { "locale": "cs-CZ", "name": "ZTEST" }, { "locale": "da-DK", "name": "ZTEST" }, { "locale": "de-DE", "name": "ZTEST" }, { "locale": "el-GR", "name": "ZTEST" }, { "locale": "en-AU", "name": "ZTEST" }, { "locale": "en-GB", "name": "ZTEST" }, { "locale": "en-US", "name": "ZTEST" }, { "locale": "es-ES", "name": "PRUEBA.Z" }, { "locale": "et-EE", "name": "ZTEST" }, { "locale": "fi-FI", "name": "ZTESTI" }, { "locale": "fr-FR", "name": "TEST.Z*" }, { "locale": "he-IL", "name": "ZTEST" }, { "locale": "hr-HR", "name": "ZTEST" }, { "locale": "hu-HU", "name": "Z.PRÓBA" }, { "locale": "id-ID", "name": "ZTEST" }, { "locale": "it-IT", "name": "ZTEST" }, { "locale": "ja-JP", "name": "ZTEST" }, { "locale": "ko-KR", "name": "ZTEST" }, { "locale": "lt-LT", "name": "ZTEST" }, { "locale": "lv-LV", "name": "ZTEST" }, { "locale": "nb-NO", "name": "ZTEST" }, { "locale": "nl-NL", "name": "Z.TOETS" }, { "locale": "pl-PL", "name": "TEST.Z" }, { "locale": "pt-BR", "name": "ZTEST" }, { "locale": "pt-PT", "name": "TESTEZ" }, { "locale": "ro-RO", "name": "ZTEST" }, { "locale": "ru-RU", "name": "ZТЕСТ" }, { "locale": "sk-SK", "name": "ZTEST" }, { "locale": "sl-SI", "name": "ZTEST" }, { "locale": "sr-Latn-RS", "name": "ZTEST" }, { "locale": "sv-SE", "name": "ZTEST" }, { "locale": "th-TH", "name": "ZTEST" }, { "locale": "tr-TR", "name": "ZTEST" }, { "locale": "uk-UA", "name": "ZTEST" }, { "locale": "vi-VN", "name": "ZTEST" }, { "locale": "zh-CN", "name": "ZTEST" }, { "locale": "zh-HK", "name": "ZTEST" }, { "locale": "zh-TW", "name": "ZTEST" } ], "signature": { "display": "ZTEST(array, x, [sigma])", "parameters": [ { "description": null, "name": "array", "optional": false, "repeats": false }, { "description": null, "name": "x", "optional": false, "repeats": false }, { "description": null, "name": "sigma", "optional": true, "repeats": false } ], "trailing_repeats": false }, "surface_name": "ZTEST", "version_marker": null, "xlcall": { "code": "324", "symbol": "xlfZtest" } }, "microsoft": "https://support.microsoft.com/en-us/office/ztest-function-8f33be8a-6bd6-4ecc-8e3a-d9a4420c4a6a" }, "try_it": { "formula": "=ZTEST({1,2,3},2,1)" }, "url": "https://handbook.dnacalc.com/functions/ZTEST.html", "variants": [], "versions": [] }