ZTEST

ZTEST is the pre-2010 spelling of Z.TEST and its page publishes the same four example rows on the same data, =ZTEST(A2:A11,4) = 0.090574 among them. DERIVATION from the identity the page publishes AS TEXT (this page carries no equation images at all): "Z.TEST(array,x) = 1-Norm.S.Dist((Average(array)- x) / (STDEV(array)/sqrt(n)),TRUE)" when sigma is omitted. With n = 10, AVERAGE = 51/10 = 5.1 and the SAMPLE standard deviation (n-1 divisor), the standard normal CDF was evaluated as erfc(-z/sqrt(2))/2 at 50 digits -- not from a statistics library's norm.cdf. NOTE ON WHICH PAGE WAS CITED FOR THE FORMULA: the ZTEST page states its two equations only as IMAGES (awfztest.gif, awfztsta.gif) with a textual legend, while the Z.TEST page states the NORM.S.DIST identity in text; the derivation therefore follows the Z.TEST page's textual form, which the legend on this page matches term for term ("x is the sample mean AVERAGE(array); s is the sample standard deviation STDEV(array); and n is the number of observations in the sample COUNT(array)"). Microsoft's page was read live on 2026-08-31 at https://support.microsoft.com/en-us/excel/functions/ztest-function. FETCH NOTE FOR THIS BATCH: batch F recorded every /en-us/office/<name>-function-<guid> URL returning Microsoft's 'Sorry, the page you're looking for can't be found' body; today BOTH paths serve the article again -- the GUID form redirects to /en-us/excel/functions/<slug>-function -- and every page cited in this batch came back complete (217-223 KB) in one or two attempts, with no 87 KB stub responses. Nothing here is sourced from a search snippet or a mirror.

Microsoft's ZTEST page publishes 0.863043 for this row, matching its Z.TEST twin.

The ZTEST page's Important box directs readers to Z.TEST and the two are documented identically. A structural assertion with no derived constant, checking the engine's two spellings against each other.

The alias check repeated on the optional third argument, which no published example on either page exercises -- the likeliest place for two spellings to drift apart unnoticed.

Asserted at twelve places from the derivation: 0.090574196851.

The Remarks publish: "If array is empty, ZTEST returns the #N/A error value." A20:A21 IS DELIBERATELY BLANK AND UNPOPULATED; emptiness is the whole content of the case.

ZTEST is the pre-2010 spelling of Z.TEST and its page publishes the same four example rows on the same data, =ZTEST(A2:A11,4) = 0.090574 among them. DERIVATION from the identity the page publishes AS TEXT (this page carries no equation images at all): "Z.TEST(array,x) = 1-Norm.S.Dist((Average(array)- x) / (STDEV(array)/sqrt(n)),TRUE)" when sigma is omitted. With n = 10, AVERAGE = 51/10 = 5.1 and the SAMPLE standard deviation (n-1 divisor), the standard normal CDF was evaluated as erfc(-z/sqrt(2))/2 at 50 digits -- not from a statistics library's norm.cdf. NOTE ON WHICH PAGE WAS CITED FOR THE FORMULA: the ZTEST page states its two equations only as IMAGES (awfztest.gif, awfztsta.gif) with a textual legend, while the Z.TEST page states the NORM.S.DIST identity in text; the derivation therefore follows the Z.TEST page's textual form, which the legend on this page matches term for term ("x is the sample mean AVERAGE(array); s is the sample standard deviation STDEV(array); and n is the number of observations in the sample COUNT(array)"). Microsoft's page was read live on 2026-08-31 at https://support.microsoft.com/en-us/excel/functions/ztest-function. FETCH NOTE FOR THIS BATCH: batch F recorded every /en-us/office/<name>-function-<guid> URL returning Microsoft's 'Sorry, the page you're looking for can't be found' body; today BOTH paths serve the article again -- the GUID form redirects to /en-us/excel/functions/<slug>-function -- and every page cited in this batch came back complete (217-223 KB) in one or two attempts, with no 87 KB stub responses. Nothing here is sourced from a search snippet or a mirror.

Microsoft's ZTEST page publishes 0.863043 for this row, matching its Z.TEST twin.

The ZTEST page's Important box directs readers to Z.TEST and the two are documented identically. A structural assertion with no derived constant, checking the engine's two spellings against each other.

The alias check repeated on the optional third argument, which no published example on either page exercises -- the likeliest place for two spellings to drift apart unnoticed.

Asserted at twelve places from the derivation: 0.090574196851.

The Remarks publish: "If array is empty, ZTEST returns the #N/A error value." A20:A21 IS DELIBERATELY BLANK AND UNPOPULATED; emptiness is the whole content of the case.

ZTEST is the pre-2010 spelling of Z.TEST and its page publishes the same four example rows on the same data, =ZTEST(A2:A11,4) = 0.090574 among them. DERIVATION from the identity the page publishes AS TEXT (this page carries no equation images at all): "Z.TEST(array,x) = 1-Norm.S.Dist((Average(array)- x) / (STDEV(array)/sqrt(n)),TRUE)" when sigma is omitted. With n = 10, AVERAGE = 51/10 = 5.1 and the SAMPLE standard deviation (n-1 divisor), the standard normal CDF was evaluated as erfc(-z/sqrt(2))/2 at 50 digits -- not from a statistics library's norm.cdf. NOTE ON WHICH PAGE WAS CITED FOR THE FORMULA: the ZTEST page states its two equations only as IMAGES (awfztest.gif, awfztsta.gif) with a textual legend, while the Z.TEST page states the NORM.S.DIST identity in text; the derivation therefore follows the Z.TEST page's textual form, which the legend on this page matches term for term ("x is the sample mean AVERAGE(array); s is the sample standard deviation STDEV(array); and n is the number of observations in the sample COUNT(array)"). Microsoft's page was read live on 2026-08-31 at https://support.microsoft.com/en-us/excel/functions/ztest-function. FETCH NOTE FOR THIS BATCH: batch F recorded every /en-us/office/<name>-function-<guid> URL returning Microsoft's 'Sorry, the page you're looking for can't be found' body; today BOTH paths serve the article again -- the GUID form redirects to /en-us/excel/functions/<slug>-function -- and every page cited in this batch came back complete (217-223 KB) in one or two attempts, with no 87 KB stub responses. Nothing here is sourced from a search snippet or a mirror.

Microsoft's ZTEST page publishes 0.863043 for this row, matching its Z.TEST twin.

The ZTEST page's Important box directs readers to Z.TEST and the two are documented identically. A structural assertion with no derived constant, checking the engine's two spellings against each other.

The alias check repeated on the optional third argument, which no published example on either page exercises -- the likeliest place for two spellings to drift apart unnoticed.

Asserted at twelve places from the derivation: 0.090574196851.

The Remarks publish: "If array is empty, ZTEST returns the #N/A error value." A20:A21 IS DELIBERATELY BLANK AND UNPOPULATED; emptiness is the whole content of the case.