Creating Multiple Frequency Histograms for Two or More Columns of Values

RockWorks | Utilities | Statistics | Histogram | Multiple

This program is used to read two or more adjacent columns of data from the datasheet and, for each, determine the frequency or percentage of the total number of measurements for that variable that falls in each user-defined grouping or "cell."  For each column of data, these values are represented as a bar histogram plot.  The 2+ histogram plots are combined for display in a single diagram.

Menu Options
Step-by-Step Summary

Menu Options

• Input Columns: Use these prompts, along the left of the window, to define the data to be processed.
  • Starting Column: Select the first (lefthand-most) column containing the data values to be read and displayed in a histogram plot.
  • Ending Column: Select the last (righthand-most) column of data values to be read.  The program will create a histogram plot for the starting column, ending column, and all columns in between.  See Inserting Columns and Deleting Columns if you need to reorganize your datasheet.
     
• Histograms per row: Click on this item to define the number of histograms to be plotted horizontally before a new row is begun.
   
• Scaling + Bin Size: Expand this to designate the width of each histogram bin as they will be displayed on the histogram plot, and to determine whether the bins are to be displayed at a linear or logarithmic scale.  Choose Linear or Logarithmic scaling. The scaling scheme you select will determine your options for selecting the bar widths. Expand the selected item for further options. (More.)
   
• Bin Colors: Expand this item to select how the histogram bars are to be filled. (More.)
  
  
• Filtering: Insert a check to activate a filter for the values, and expand the item to set the filtering parameters.
  • Minimum Value: Click to enter the minimum value to be included in the histogram.
  • Maximum Value: Click to type in the maximum value to be included in the histogram.
    
    
• Plot Statistics: Insert a check here to include labels that represent the groupings of histogram bars into mean + and - 1SD, 2SD, 3SD and 4SD. Expand this item to establish the label color and size (as a percent of diagram width.). (More.)
   
• Plot X Axis Labels: Insert a check here to plot labels along the bottom axis that represent the real number units of the variable being plotted. Expand this item to establish the label color and size (as percent diagram width).
   
• Plot Y Axis Labels: Insert a check in this box to plot labels along the vertical axis that represent the frequency units. Expand this item to establish the color, size and units. 
  • Plot as Percentages: Insert a check in this check-box if you want the units to represent percent. If this box is cleared, the units will represent actual occurrences.
  
  
• Statistical Legend: Insert a check here to include a legend listing a statistical summary for the data.
  Expand this heading to access the legend layout options. (More.)
   
• Fixed Diagram Width:Height Ratio:  Check this box if you wish to define a specific size ratio for the graph, excluding the legend (default 2.0 which representes twice as wide as high).
  
  
• X-Spacing (% of Width): This defines the spacing of the individual histograms across the composite diagram, as a percent of the diagram width.
  
  
• Y-Spacing (% of Width): This defines the spacing of the individual histograms across the composite diagram, as a percent of the diagram height.
   

Step-by-Step Summary

1. Access the RockWorks Utilities program tab. 
2. Enter/open/import your data into the datasheet. Be sure that the file contains at least two columns of data to be displayed in the histogram plots. 
3. Select the Statistics | Histogram | Multiple menu option. 
4. In the displayed dialog box enter the requested information, discussed above. 
5. Click the Process button to continue.
   
   The program will read the real number values from the requested datasheet columns, and filter any low or high values if requested. For each column, it will display the data range in a window if Confirm Range is activated. 
    
6. For each data column, you can override the minimum and/or maximum entries to extend the range of the axis. For example, if the data range as displayed in the window is 21 - 74, then that would be the range of the horizontal axis if left unchanged. If overridden to 0 - 100, then the axis itself would extend from 0 to 100 units. The prompts will be displayed in the order of the data columns.
   
   
7. Click OK in each Set Histogram Range window to continue. 
   
   For each data column, the program will determine the number of remaining samples that fall into each of the histogram "bins," counting them either as actual frequencies or as percent. The completed histogram plots will be compiled into a single diagram and displayed in a RockPlot2D tab in the Options window.
    
8. You can adjust any of the diagram option in the pane to the left (adjust color scheme, change scaling, etc.) and then click the Process button again to regenerate the histogram.
   
   ! Each time you click the Process button, the existing display will be replaced. 
    
9. View / save / manipulate / print / export the diagram in the RockPlot2D window. 
   
   

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