Nonparametric Correlations

Select Correlations (Spearman, Kendall tau, gamma ) from the Nonparametric Statistics Startup Panel - Quick tab to display the Nonparametric Correlations dialog box, which contains two tabs: Quick and Advanced.

Variables. Click the Variables button to display the standard variable selection dialog box. Use these options to select at least two variables for which correlations will be computed (each variable in the first list will be correlated with each variable in the second list).

Compute. With the options (described below) in the Compute box, you can choose to compute single nonparametric correlations or matrices of nonparametric correlations. A useful Graph of Input Data for the results spreadsheet is the scatterplot, from which you can easily graph the correlations.

Detailed report. Selecting Detailed report results not only in the computation of the correlations between the specified variables (see above), but also in the Valid n, t-value, and p-value for each correlation.

Matrix of two lists. Select Matrix of two lists to compute only the correlations between the variables specified in the first list against the variables specified in the second list.

Square matrix. Select Square matrix to compute correlations from a single list of variables (resulting in a square matrix of correlations). Note that if you have already specified two lists of variables and then select this option, the two lists will be "stacked" to make one list of variables.

Spearman R. Select the Spearman R button to display either the standard variable selection dialog or the results of the analysis (if you have already selected the variables). Spearman R assumes that the variables under consideration were measured on at least an ordinal (rank order) scale, that is, that the individual observations can be ranked into two ordered series.

Cancel. Click the Cancel button to close the dialog box and return to the Nonparametric Statistics Startup Panel.

Options. Click the Options button to display the Options menu.

By Group.  Click the By Group button to display the By Group specification dialog box.

Select Cases. Click the Select Cases 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, syntax summary, and dialog description.

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.

p-value for highlighting. The default p-value for highlighting is .05. You can adjust this p-value by entering a new value in the text box or using the microscrolls. On the summary spreadsheets, STATISTICA will highlight all p-values that are equal to or less than the value specified in this field. For more details on p-value, see Elementary Concepts.