# TTestw\_lower - script and chart function

TTestw\_lower() returns the aggregated value for the lower end of the confidence interval for two independent series of values.

This function applies to two independent samples student's t-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:

TTestw\_lower (weight, grp, value [, sig [, eq\_var]])

Return data type: numeric

Arguments:

* 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.
* weight: Each value in value can be counted one or more times according to a corresponding weight value in weight.
* 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:

`TTestw_lower( Weight, Group, Value )` `TTestw_lower( Weight, Group, Value, sig, false )`

## Learn more

* [Creating a typical t-test report](https://help.qlik.com/en-US/qlikview/September2026/Subsystems/Client/Content/QV_QlikView/ChartFunctions/StatisticalTestFunctions/ttest/ttest_t_example.htm)