Fitting Discrete Distributions - Options Tab

Select the Options tab of the Fitting Discrete Distributions dialog box to access the options described here. From this tab, you can plot either the frequency or cumulative distribution and the raw frequencies or the relative frequencies when you click the Plot of observed and expected distribution button on the Quick tab.

Kolmogorov-Smirnov test. Use the options in the Kolmogorov-Smirnov test group box to display results of the Kolmogorov-Smirnov test. The Kolmogorov-Smirnov test can be computed either from the tabulated values [which is faster; choose the Yes (categorized) option button] or based on the raw data [which is slower; choose the Yes (continuous) distribution button].

No. Select the No option button in the Kolmogorov-Smirnov test group box if you do not want to display the results of the Kolmogorov-Smirnov test.

Yes (categorized). Select the Yes (categorized) option button in the Kolmogorov-Smirnov test group box to display the results of the categorized Kolmogorov-Smirnov test. In this case (categorized), STATISTICA will compute the D-max statistic from the tabulated data in the spreadsheet. If the Kolmogorov-Smirnov test is statistically significant, we reject the hypothesis that the observed data follow the hypothesized distribution.

Yes (continuous). Select the Yes (continuous) option button in the Kolmogorov-Smirnov test group box to display the results of the continuous Kolmogorov-Smirnov test. In this case (continuous), STATISTICA will "step" through the sorted observed data and compute the cumulative expected frequency at each point; the Kolmogorov D-max statistic is the largest absolute difference between the cumulative observed and expected distribution.

Graph. Use the options in the Graph group box to affect the graph of the distribution that is displayed when you click the Plot of observed and expected distribution button on the Quick tab.

Plot distribution. Use the options in the Plot distribution group box to plot either the Frequency distributions or the Cumulative distribution when you click the Plot of observed and expected distribution button.

Plot raw frequencies or %. Use the options in the Plot raw frequencies or % group box to plot either the Raw frequencies or the Relative frequencies (%) when you click the Plot of observed and expected distribution button.

Chi-Square test. Select the Combine Categories check box in the Chi-Square test group box to combine categories with expected frequencies less than or equal 5. If the expected frequency is found to be less than or equal 5, STATISTICA will add the expected frequency for the respective category to that of the next adjacent category. This combining of frequencies will continue until a minimum expected cumulative frequency of greater than 5 is reached. If this cannot be achieved, the expected frequency will be added to the last category at which the expected frequency measured greater than 5. Note that the degrees of freedom for the Chi-square test will be adjusted accordingly (to reflect the number of categories after combining categories with small numbers of expected frequencies).