Workspace Node: 2D Means with Error Plots - Quick Tab

The 2D Means with Error Plots 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.

Variables

Click the Variables button to display a variable selection dialog box, in which you select the Dependent variable and the Grouping variable for creating the graph.

The dependent variable values will be used in calculating the respective statistics that define the components of the graph (e.g., means, medians, standard deviations, etc.), while the grouping variable will be used to categorize the data, using the method of categorization as selected via the options in the Grouping intervals group. Note that more than one dependent variable can be selected and selection of the Grouping variable is optional. If you select multiple dependent variables and the Regular graph format (see above), a sequence of Means with Error Plots (one for each dependent variable) will be produced in separate graphs. If the graph Format is set to Multiple, then the Means with Error Plots for all the selected dependent variables will be combined into a single graph. The selection of variables that you make will be displayed in the area of the dialog box below the Variables button.

Graph type

Select the type of Mean with Error Plot to be plotted from the Graph type list. Click a link below for a brief description of that type of graph.

Whiskers

High-Low Close

Columns

You can also choose between two types of graph formats. Click a link below to learn more about it.

Regular

Multiple

The choice of the combination of the Graph type and format will depend on the objective you have in mind. For example, if you have selected more than one dependent variable and your aim is to compare their distributions, you may select Whiskers with Multiple graph format.

Grouping intervals

Use the options in this group box to select a method  (Integer mode, Unique Values, Categories, or Codes ) to define the manner in which the values in the chosen grouping variable will be used to determine the categories for the graph; additional options are available on the Advanced tab. Note that separate means (medians, etc., as chosen by the user) will be computed for each group as defined by the values in the grouping variable. The methods for categorizing the values in the grouping variable are discussed in detail in Methods of Categorization.

Whisker

The options in this group box are used to specify the range of Whiskers or High-Low Close, i.e., to define the error ranges.

Value

Use the Value drop-down box to specify how the range of Whiskers or High-Low Close are computed (Conf. Interval, Non-outlier range, Min-max, or Constant). If you select Conf. Interval, the range will be displayed as the confidence interval around the mean value. If you select Non-outlier range, Statistica determines which points in the data are outliers (see Outliers and extremes), and then uses the highest and lowest data points that are closest to the outliers (but are not outliers) to determine the range in the plot. On the other hand, the option Min-Max uses the minimum and maximum values of the data to determine the range, without considering whether or not these values are outliers. If you choose option Constant, the specified constant will be added/subtracted from the chosen center point (mean or median), to define the range around that center point.  

Probability/Coefficient

If you specify the Value option (see above) as Conf. Interval, you also need to specify a value between 0.15 and .99 in the Probability edit field. This value will be used to determine the length of the Whiskers or High-Low Close around the Mean value, based on the standard error for the respective means, and the standard normal (z) value associated with the chosen probability. When you specify the Value as Non-outlier range or Min-max (see above), you also need to specify a value in the Coefficient edit field by which the selected Value will be multiplied to determine the range. If the Value option is specified as Constant, the value of the Coefficient itself determines the range (no multiplier is used). By default the value of the Coefficient is 1.

Frequency / severity plot. When this check box is selected, a line of means is overlaid on the histogram. The line doesn't show raw values, but is relative to the mean in the most frequent category.

Layout. Select the type of layout for the graph(s).

Separate

Select this option button to produce a Separate plot layout (where each subset of cases is displayed in a separate graph) for the categorized plots.

Overlaid

Select this option button to produce an Overlaid plot layout (where all subsets are overlaid in one graph and identified by patterns and colors) for the categorized plots.

Note: The graph icon displayed represents the currently selected Graph type (Whiskers or High-Low Close) and the Mean. It also previews the selected Value (Conf. Interval, Non-outlier range, Min-max, or Constant) that will define the Mean with Error Plot that you are about to create as specified in the Whisker group box.

Options / C / W. See Common Options.

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

See also, Advanced tab, Appearance tab, Categorized tab, Options 1 tab, Options 2 tab, and Home tab.