Descriptive Statistics

On the Basic Statistics and Tables dialog box - Quick tab, select Descriptive Statistics and click the OK button to display the Descriptive Statistics dialog box, which contains seven tabs: Quick, Advanced, Normality, Prob. & Scatterplots, Categ. Plots, Robust, and Options. See also, the Descriptive Statistics Overview.

Variables. Click this button to display a variable selection dialog box, in which you select the variables for the analysis.

Summary. Click this button to produce a spreadsheet with the descriptive statistics for the selected variables. You can request specific descriptive statistics on the Advanced tab.

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.

By Group. Click this button to display the By Group specifications dialog box.

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 current 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 contains options to adjust the contribution of individual cases to the outcome of the current analysis by weighting those cases in proportion to the values of a selected variable.

Wghtd momnts. Select the Wghtd momnts (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 Wghtd 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 Wghtd moments check box is selected, several graphics options are not available. For more information on options for using integer case weights, see also Selecting a weighting variable.

MD deletion. If Casewise deletion of missing data is selected, Statistica ignores 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 are included in the analyses for the respective variables (resulting possibly in unequal valid N per variable).

Note: other descriptive statistics. The Basic Statistics and Tables module includes a selection of the most often used descriptive statistics. An additional set of ordinal descriptive statistics and some less frequently-used ones (e.g., user-specified percentiles, harmonic means, etc.) are included in the Nonparametric Statistics module; in that module a variety of non-normal distributions can also be fit to the data. More specialized descriptive statistics are included in other modules of Statistica. See also, Graphs of Input Data and Exploratory Data Analysis and Data Mining Techniques.