ZTEST

ZTEST(array, x [,sigma])

Returns the probability that the supplied hypothesized sample mean is greater than the mean of the supplied data values.

array	The array or range of data against which to test x.
x	The value to test.
sigma	(Optional) The population (known) standard deviation.

REMARKS

* This function is only available for backwards compatibility and should not be used.
* Z.TEST was added in Excel 2010 to replace this function.
* If array is empty, then #N/A is returned.
* The z-test generates a standard score for x with respect to the data set, array, and returns the two-tailed probability for the normal distribution.
* You can use this function to assess the likelihood that a particular observation is drawn from a particular population.
* This is similar to the CHITEST, FTEST and TTEST functions.
* For the Microsoft documentation refer to support.microsoft.com

	A
1	=ZTEST({3, 6, 7, 8, 6, 5, 4, 2, 1, 9}, 4) = 0.091
2	=ZTEST({2, 4, 6, 8, 10}, 3) = 0.017