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.

[Example:

ZTEST({3,6,7,8,6,5,4,2,1,9},4) results in 0.090574197
ZTEST({3,6,7,8,6,5,4,2,1,9},6) results in 0.863043389

end example]