Workspace Node: t-Test, Independent Samples, by Variables - Specifications - Quick Tab

The t-Test for Independent Samples, by Variables workspace node can be accessed from the Feature Finder, ribbon bar, or Node Browser. The Quick tab of the specifications dialog box is displayed by default when you double-click the node.

For simple data analyses, it is sometimes easier to enter the data so that each column in the data file (variable) represents the responses of one group (e.g., the data for all male respondents entered into the first column of the file, and the data for all female respondents entered into the second column). If your data are arranged in this manner, use this node. Otherwise, use the t-Test, Independent, by Groups node. See also, t-Test for Independent Samples Overview.

Element Name Description
Variables (groups) Click this button to display a standard variable selection dialog box. Specify two lists of variables. Since this setting of the input file combo box assumes that each variable represents the data for one group, each variable (group) in the first list will be compared with each variable (group) in the second list.
Weighted moments Select the Weighted moments check box to specify that each observation contributes the weighting variable's value for that observation. The weight values need not be integers. This module can use fractional case weights in most computations. Some other modules use case weights as integer case multipliers or frequency values. This option is available only after you have defined a weight variable via the W option described below.
DF = W-1 / N-1 When the Weighted moments check box is selected, some statistics related to the moments (e.g., standard deviations and variances, skewness, kurtosis) can be based on the sum of the weight values for the weighting variable (W-1), or on the number of (unweighted) observations (N-1). The sums (and means), and sums of squares and cross products will always be based on the weighted values of the respective observations. However, in computations requiring the degrees of freedom (e.g., standard deviation, t-test, etc.), the value for the degrees of freedom can either be computed as the sum of the weight values minus one, or as the number of observations minus one. Moment statistics (except for the mean) are based on the sum of the weight values for the weighting variable when the W-1 option button is selected, and are based on the number of (unweighted) observations when the N-1 option button is selected. When the Weighted moments check box is selected, several graphics options will not be available. For more information on options for using integer case weights, see also Selecting a Weighting Variable.
MD deletion When Casewise deletion of missing data is selected, Statistica ignores all cases that have missing data for any of the variables selected in the list. When Pairwise deletion of missing data is selected, all valid data points will be included in the analyses for the respective variables (resulting possibly in unequal valid N per variable).

Options / C / W. See Common Options.

OK Click the OK button to accept all the specifications made in the dialog box and to close it. The analysis results are placed in the Reporting Documents after running (updating) the project.

See also, Results - Quick tab, Results - Options tab, Downstream tab, and Home tab.