ZTestw_sterr() returns the aggregated z-test standard error of the mean difference for a series of values.
This function applies to z-tests where the input data series is given in weighted two-column format.
If the function is used in the load script, the values are iterated over a number of records as defined by a group by clause.
If the function is used in a chart expression, the values are iterated over the chart dimensions.
Syntax:
ZTestw_sterr (weight, value [, sigma])
Return data type: numeric
Arguments:
- value: The values should be returned by value. A sample mean of 0 is assumed. If you want the test to be performed around another mean, subtract that value from the sample values.
- weight: Each sample value in value can be counted one or more times according to a corresponding weight value in weight.
- sigma: If known, the standard deviation can be stated in sigma. If sigma is omitted the actual sample standard deviation will be used.
Limitations:
Text values, NULL values and missing values in the expression value will result in the function returning NULL.
Example:
ZTestw_sterr( Weight, Value-TestValue)
