ZTestw_lower() returns the aggregated value for the lower end of the confidence interval for two independent series of values.
If the function is used in the data 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_lower (grp, value [, sig [, eq_var]])
Return data type: numeric
Arguments:
| Argument | Description |
|---|---|
| value | The sample values to be evaluated. The sample values must be logically grouped as specified by exactly two values in group. If a field name for the sample values is not provided in the load script, the field will automatically be named Value. |
| grp | The field containing the names of each of the two sample groups. If a field name for the group is not provided in the load script, the field will automatically be given the name Type. |
| sig | The two-tailed level of significance can be specified in sig. If omitted, sig is set to 0.025, resulting in a 95% confidence interval. |
| eq_var | If eq_var is specified as False (0), separate variances of the two samples will be assumed. If eq_var is specified as True (1), equal variances between the samples will be assumed. |
Limitations:
Text values, NULL values and missing values in the expression value will result in the function returning NULL.
Examples:
ZTestw_lower( Group, Value )
ZTestw_lower( Group, Value, sig, false )