Z.TEST
TheZ.TEST
formula returns the probability of a certain value occurring in a normal distribution. This formula is commonly used to test whether two samples have the same mean by comparing their Z scores. The formula returns a value between 0 and 1, with a result closer to 1 indicating a higher likelihood that the value could occur by chance.
 How to use
Z.TEST
formula?  Examples of using
Z.TEST
formula Z.TEST
formula not working? Similar formulas to
Z.TEST
Usage
Use the Z.TEST
formula with the syntax shown below, it has 2 required parameters and 1 optional parameter:
 data (required):
The range of cells or array containing the data to be tested.  value (required):
The value to be tested.  standard_deviation (optional):
An optional parameter representing the population standard deviation. If not provided, the sample standard deviation will be used instead.
Examples
Here are a few example use cases that explain how to use theZ.TEST
formula in Google Sheets.
Testing for significant differences in sample means
By using the Z.TEST
formula, you can quickly test whether two samples have significantly different means.
Determining the probability of a value occurring in a normal distribution
You can use Z.TEST
to determine the probability of a given value occurring in a normal distribution with a known mean and standard deviation.
Testing for the significance of correlation coefficients
The Z.TEST
formula can also be used to test whether the correlation coefficient between two variables is significantly different from zero.
Common Mistakes
Z.TEST
not working? Here are some common mistakes people make when using the Z.TEST
Google Sheets Formula:
Using incorrect data range
One common mistake when using the Z.TEST
function is using an incorrect range of data, such as including blank cells or nonnumeric values in the range.
Incorrectly specifying standard deviation
Another common mistake is incorrectly specifying the standard deviation of the population, such as using the standard deviation of the sample instead of the known standard deviation.
Confusing onetailed and twotailed tests
A common mistake when using the Z.TEST
function is confusing onetailed and twotailed tests, which can result in incorrect calculations of statistical significance.
Related Formulas
The following functions are similar to Z.TEST
or are often used with it in a formula:

T.TEST
The
T.TEST
function calculates the probability associated with a Student's ttest. This function is commonly used in statistics to determine whether two samples are likely to have come from the same two underlying populations that have the same mean. It returns the probability that the two samples are different. The function assumes that the two samples are independent of each other and have equal variances. 
CHISQ.TEST
The
CHISQ.TEST
formula calculates the test for independence of two categorical ranges of data using the chisquared distribution. It returns the probability that any observed differences between the two ranges are due to chance. This formula is commonly used in hypothesis testing to determine whether there is a significant association between two variables. 
CORREL
The
CORREL
formula returns the correlation coefficient between two sets of data. This coefficient represents the strength of the linear relationship between the two sets of data, with values ranging from 1 (perfect negative correlation) to 1 (perfect positive correlation). 
STDEV
The
STDEV
function calculates the standard deviation of a set of numbers. It measures the amount of variation or dispersion of a set of values from the average (mean) value. It is commonly used in statistics to determine the spread of a data set. The values can be supplied as individual cells, ranges, or constants.
Learn More
You can learn more about the Z.TEST
Google Sheets function on Google Support.