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In this article
Z.TEST returns the one-tailed p-value for whether a sample mean is higher than a claimed value.
Syntax
=Z.TEST(array, x, [sigma])| Argument | What it means |
|---|---|
x |
The claimed mean. |
Examples
Example 1
=Z.TEST(B2:B51, 500)Are packets really filled above 500 g on average?
Z.TEST in practice
Where you will use it
- Is a sample mean above a target?
- Quality vs spec
- Large-sample tests
Worked example
| Target mean | Formula | Result |
|---|---|---|
| 120 | =ROUND(Z.TEST({120,135,128,160,95,140,132},A2),4) | 0.091 |
| 130 | =ROUND(Z.TEST({120,135,128,160,95,140,132},A3),4) | 0.5 |
| 140 | =ROUND(Z.TEST({120,135,128,160,95,140,132},A4),4) | 0.909 |
Results calculated in Excel.
Mistakes people make
| Mistake | What to do instead |
|---|---|
| One-tailed | Z.TEST returns a one-tailed p-value |
| Small samples | Prefer T.TEST |
Related functions
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📎 Practice files for this article
- 📗Practice workbook: Statistics advanced33 tasks on realistic sales data — type your formula, the Check column turns green when it is right. Answers sheet included.⬇ XLSX · 36 KB
Free to use for learning. Files with macros (.bas) are plain text — import them with Alt+F11 → File → Import File, and always test on a copy.
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