Help Manual

Contents






Sigma Magic Help Version 17

Multi-Vari Chart

Overview

Multi Vari charts can help identify the source of variation by plotting the data for several variables on a single chart. A multi-vari chart is usually plotted for continuous data concerning positional variation, short-term variation, and long-term variation. By understanding where the variation is coming from, actions can be taken to reduce the total variation in the output. For example, you are trying to reduce the variation from a piece of equipment. You collect data at different product locations, at different times during the data, and on different days of the week. This data can then be plotted on a Multi-Vari chart to determine if the most variation comes from different positions on the product, from short-term or long-term variation.

This template can be added to your active workbook by clicking on Graph and then selecting Multi Vari Chart.

Inputs

Click on Analysis Setup to open the menu options for this template. A sample screenshot of the menu is shown below.
inputs
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Chart Type: Specify the format of the chart. The following options are available:
OptionDescription
1 VariableCreate a Multi Vari chart with a single X variable.
2 VariablesCreate a Multi Vari chart with two X variables.
3 VariablesCreate a Multi Vari chart with three X variables.
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Primary Axis: Specify the variable to use for the primary axis. This is the horizontal axis at the bottom of the graph.
OptionDescription
PositionalUse the positional variable for the primary axis.
Short TermUse the short-term variable for the primary axis.
Long TermUse the long-term variable for the primary axis.
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Legend Axis: Specify the variable to use for the legend axis. This is the axis variable that is used to generate the legend axis. This option is available only if the number of plot variables is set to 2 or greater.
OptionDescription
PositionalUse the positional variable for the legend axis.
Short TermUse the short-term variable for the legend axis.
Long TermUse the long-term variable for the legend axis.
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Secondary Axis: Specify the variable to use for the secondary axis. This is the horizontal axis at the top of the graph. This option is available only if the number of variables is set to 3.
OptionDescription
PositionalUse the positional variable for the secondary axis.
Short TermUse the short-term variable for the secondary axis.
Long TermUse the long-term variable for the secondary axis.
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Help Button: Click on this button to open the help file for this topic.
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Cancel Button: Click on this button to discard any changes and close the dialog box.
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OK Button: If possible, click this button to save any changes and compute the analysis outputs.

Data

You will see the following dialog box if you click the Data button. Here, you can specify the data required for this analysis. Data
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Search Data: The available data displays all the columns of data that are available for analysis. You can use the search bar to filter this list and speed up the search for the right data for analysis. Enter a few characters in the search field, and the software will filter and display the filtered data in the Available Data box.
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Available Data: The available data box contains the list of data available for analysis. If your workbook has no data in tabular format, this box will display "No Data Found." The information displayed in this box includes the row number, whether the data is Numeric (N) or Text (T), and the name of the column variable. Note that the software displays data from all the tables in the current workbook. Even though data within the same table have unique column names, columns across different tables can have similar names. Hence, it is crucial that you not only specify the column name but also the table name.
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Add or View Data: Click on this button to add more data to your workbook for analysis or to view more details about the data listed in the available data box. When you click on this button, it opens the Data Editor dialog box, where you can import more data into your workbook. You can also switch from the list view to a table view to see the individual data values for each column.
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Required Data: The code for the required data specifies what data can be specified for that box. An example code is N: 2-4. If the code starts with an N, select only numeric columns. If the code begins with a T, you can select numeric and text columns. The numbers to the right of the colon specify the min-max values. For example, if the min-max values are 2-4, you must select a minimum of 2 columns of data and a maximum of 4 columns in this box. If the minimum value is 0, then no data is required to be specified for this box.
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Select Button: Click on this button to select the data for analysis. Any data you choose for the analysis is moved to the right. To select a column, click on the columns in the Available Databox to highlight them and then click on the Select Button. A second method to choose the data is to double-click on the columns in the list of Available Data. Finally, you can drag and drop the columns you are interested in by holding down the select columns using your left mouse key and dragging and dropping them in one of the boxes on the right.
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Selected Data: The list box header will be displayed in black if the right number of data columns is specified. If sufficient data has not been specified, then the list box header will be displayed in red color. Note that you can double-click on any of the columns in this box to remove them from the box.
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Response Variable: This list box contains the response data to create the multi-vari chart. This list box is mandatory, and one column must be specified. Note that the values specified in this column must be numeric.
6b
Factor 1 Variable: This list box contains the categories to use to create the multi-vari chart. This list box is mandatory. This list box contains the group information for the first variable. Note that the number of rows of data in this column should be the same as the number of rows of the response variable.
6c
Factor 2 Variable: This list box contains the categories to use to create the multi-vari chart. This list box contains the group information for the second variable. Note that the number of rows of data in this column should be the same as the number of rows of the response variable. This list box will only be displayed if you have selected that you want to create the multi-virus chart for more than one variable.
6c
Factor 3 Variable: This list box contains the categories to use to create the multi-vari chart. This list box contains the group information for the third variable. Note that the number of rows of data in this column should be the same as the number of rows of the response variable. This list box will only be displayed if you have selected that you want to create the multi-vari chart for more than two variables.
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View Selection: Click on this button to view the data specified for this analysis. The data can be viewed in a tabular format or a graphical summary.

Charts

You will see the following dialog box if you click the Charts button. Charts
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Title: The system will automatically pick a title for your chart. However, if you want to override that with your title, you can specify a title for your chart here. Note that this input is optional.
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Sub Title: The system will automatically pick a subtitle for your chart. However, if you want to override that with your subtitle, specify a subtitle for your chart here. Note that this input is optional.
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X Label: The system will automatically pick a label for the x-axis. However, if you would like to override that with your label for the x-axis, you can specify a different label here. Note that this input is optional.
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Y Label: The system will automatically pick a label for the y-axis. However, if you would like to override that with your label for the y-axis, you can specify a different label here. Note that this input is optional.
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X Axis: The system will automatically pick a scale for the x-axis. However, if you would like to override that with your values for the x-axis, you can specify them here. The format for this input is to specify the minimum, increment, and maximum values separated by a semi-colon. For example, if you specify 10;20, the minimum x-axis scale is set at 10, and the maximum x-axis scale is set at 20. If you specify 10;2;20, then, in addition to minimum and maximum values, the x-axis increment is set at 2. Note that this input is currently disabled, and you cannot change this setting.
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Y Axis: The system will automatically pick a scale for the y-axis. However, if you would like to override that with your values for the y-axis, you can specify them here. The format for this input is to specify the minimum, increment, and maximum values separated by a semi-colon. For example, if you specify 10;20, the minimum y-axis scale is set at 10, and the maximum y-axis is set at 20. If you specify 10;2;20, then, in addition to minimum and maximum values, the y-axis increment is set at 2. Note that this input is optional.
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Horizontal Lines: You can specify the values here if you want to add a few extra horizontal reference lines on top of your chart. The format for this input is numeric values separated by semi-colon. For example, if you specify 12;15, two horizontal lines are plotted at Y = 12 and Y = 15, respectively. Note that this input is optional.
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Vertical Lines: You can specify the values here if you want to add a few extra vertical reference lines on top of your chart. The format for this input is numeric values separated by semi-colon. For example, if you specify 2;5, two vertical lines are plotted at X = 2 and X = 5, respectively. Note that this input is optional.

Verify

If you click the Verify button, the software will perform some checks on the data you entered. A sample screenshot of the dialog box is shown in the figure below. Verify The software checks if you have correctly specified the input options and entered the required data on the worksheet. The results of the analysis checks are listed on the right. If the checks are passed, they are shown as green-colored checkmarks. If the verification checks fail, they are shown as a red-colored cross. The verification checks are shown in the orange exclamation mark if the verification checks result in a warning. Finally, any checks required to be performed by the user are shown as blue info icons.
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Item: The left-hand side shows the major tabs and the items checked within each section
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Status: The right-hand side shows the status of the checks.
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Overall Status: The overall status of all the checks for the given analysis is shown here. The overall status check shows a green thumps-up sign if everything is okay and a red thumps-down sign if any checks have not passed. Note that you cannot proceed with generating analysis results for some analyses if the overall status is not okay.

Outputs

Click on Compute Outputs to update the output calculations. A sample screenshot of the worksheet is shown below. outputs
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Notes: The text output of the analysis is sent to the notes section. This section contains the number of data points, the number of factors, and the names of variables to plot the primary, legend, and secondary axes. The analysis results summarize the output, namely the minimum, mean, maximum values, and the range of the output data. The maximum amount of variation contributed by each of the input variables is shown. The conclusion section summarizes which variable contributes the most to the total variation.

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Graphs: The graphs section contains the Multi-Vari chart of the given data set. The black line joins the individual data points. If multiple values exist in the same setting, the graph plots the average of all the points. The black line corresponds to the averages of the data points corresponding to the legend axis. The red line joins the averages for each data point corresponding to the primary axis. The green line joins the averages for each data point corresponding to the secondary axis.

Notes

Here are a few pointers regarding this analysis:
  • You can format the graph using the standard Excel functions. However, note that if you click on Compute Outputs again, you may lose all the formatting you have done to your graph.
  • If you have missing data points, the corresponding data point is not shown on the graph, and these values are not used in the average computations.

Examples

The following examples are in the Examples folder.
  • Create a Multi-Vari chart for the data in the following file. Determine the major contributor to spread or variation (Multi Vari Chart 1.xlsx).


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