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By |Published On: January 10, 2023 at 7:27 am PST|Last Updated: January 10, 2023 at 7:27 am PST|
Log Normal Curve with Equation and 95% Confidence Interval

This tutorial will show how to use the TechGraph Editor to fit a log normal curve and the 95% confidence interval to a set of XY data points.  A log normal equation that shows the minimum, maximum, mean and SD values is displayed as well. Shown below are the settings in the Data Table and the Edit Chart used to create this chart.   

Data Table – Sample data can easily be changed or replaced by pasting data from an external worksheet.
  • Graph Type is Scatter.
  • X Data Type is Number.  X Data column contains the X values.
  • Graph A series is set to Scatter and it contains the Y values.

Note:   Click on the “Help” button on the toolbar to find out how to edit, delete, copy and paste in the Data Table.  

Edit Chart – A set of icons (Titles, Settings, X Axis, Y Axis, Curves and Error Bars) to change the settings and appearance of the chart.       

    Settings  – specify the color, marker type and size for Graph A marker.         

  •  Click on the “DarkOrchid circle” (Graph Style) to show the marker Style for Graph A pop-up.   You can change the Color, Type and Size for Graph A marker.   Click on Apply to save the changes.

     X Axis 

  • Enter values in Minimum, Maximum and Major Div to set the X Axis scale and divisions. Leave these values empty for automatic scaling.

     Y axis

  • Enter values in Minimum, Maximum and Major Div to set the Y Axis scale and divisions. Leave these values empty for automatic scaling.

     Curves & Error Bars       

  • Click on “Log Normal” (Curve Fit) for Graph A to show the Curvefit Selection for Graph A pop-up.   For this example, “Log Normal” is selected from the Selection list.  Checkbox for Show Curve Fit Equation and Show Curve Fit Legend are checked.  Checkbox for Show Confidence Curves is checked.  “95%” is selected from Confidence Level list. Click on Apply to save the changes.
  • Click on Curve Style for Graph A to show the Curve Style for Graph A pop-up.  Curve Color (“Black”) is selected for the log normal curve color.  “Black” is also selected for the Confidence color.   Use the Thickness and Line Type selection list to change the line style. Click on Apply to save the changes.

 Note:  To move the location of the polynomial equation – click on the equation and it will be outlined with “bubbles”.  Grab the center bubble and move to the desired location.                   

 

Edit Chart Toolbar Options

  •  Print Chart prints your chart.
  •  Download Image downloads your chart as an SVG(Scalable Vector Graphics) file or image file(PNG, JPEG, TIF, PDF).
  •  Drawing Objects customize your chart with labels, lines, arrows, circles, images, and logos.
 Getting Started: