ZTEST
Syntax:
ZTEST ( array , test-value [ , sigma ] )
Description: Computes the one-tailed probability-value of a z-test. For a given hypothesized population mean, test-value, ZTEST returns the probability that the sample mean would be greater than the average of observations in the data set array; that is, the observed sample mean.
Mathematical Formula:
When sigma is present:
When sigma is omitted:
where 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).
Arguments:
Name |
Type |
Description |
|---|---|---|
array |
array |
The set of numerical data against which to test test-value. |
test-value |
number |
The number to test. |
sigma |
number |
The number is the population (known) standard deviation. If omitted, the sample standard deviation is used. |
Return Type and Value: number – The one-tailed probability-value of a z-test.
However, if array is empty, the return value is unspecified.