Statistics by Groups (Breakdown)

Select Breakdown & one-way ANOVA on the Basic Statistics and Tables dialog box - Quick tab and click the OK button to display the Statistics by Groups (Breakdown) dialog box. This dialog box contains two tabs: Individual tables and Lists of tables. The options on these tabs are used to analyze statistics by groups (breakdowns). See the Breakdown Procedure Overview.

OK. Click this button to perform the specified analyses and display the Statistics by Groups Results dialog box. Note that the OK button is available when the Individual tables tab is selected.

Summary. Click this button to display the selected Output Tables and Statistics. Note that the Summary button is available when the Lists of tables tab is selected.

Cancel. Click this button to close the dialog box without performing an analysis and return to the Basic Statistics and Tables dialog box.

Options. Click this button to display the Options menu.

Select Cases. Click this button to display the Analysis/Graph Case Selection Conditions dialog box, which contains options to create conditions for which cases will be included (or excluded) in the analysis. More information is available in the case selection conditions overview and syntax summary.

W. Click the W (weight) button to display the Analysis/Graph Case Weights dialog box, which is used to adjust the contribution of individual cases to the outcome of an analysis by "weighting" those cases in proportion to the values of a selected variable.

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 above.

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 are always 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 if the W-1 option button is selected, and are based on the number of (unweighted) observations if the N-1 option button is selected. When the Weighted moments check box is selected, several graphics options are not available. For more information on options for using integer case weights, see Selecting a Weighting Variable.

MD deletion. If Casewise deletion of missing data is selected, Statistica will ignore all cases that have missing data for any of the variables selected in the list. If 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).

See also, Exploratory Data Analysis and Data Mining Techniques.