Help Manual

Contents






Sigma Magic Help Version 15

Scatter Plot

Overview

A Scatter Plot tool can be used to create a Scatter Plot for the given sets of data points. Scatter Plots can be used to compare two sets of data. Usually, both sets of data are continuous. Dot Plots can reveal if there is a positive relationship between X and Y, a negative relationship between X and Y, or no relationship between X and Y.

This tool can be added to your active workbook by clicking on Graph and then selecting Scatter Plot.

Inputs

Click on Analysis Setup to open the menu options for this tool. A sample screenshot of the menu is shown below. inputs
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Chart Type: Specify the format of the chart. This selection is not enabled since there is only one format available.
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Best Fit: Specify whether you want to display a best fit line for the scatter plot. The available options are:
OptionDescription
NoDo not display the best fit line on the scatter plot.
YesDisplay the best fit trendline on the scatter plot. Note that you can right click on the trendline and change it from linear to quadratic or other types of fit as appropriate.
3
Connector: Specify whether you want to draw a connector between the data points. The available options are:
OptionDescription
NoDo not join the data points with a connector. This is the default option.
YesConnect the data points with a connector. Make sure that the data has been collected and stored in a time-order.
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Markers: Specify the type of markers to use for the scatter plot. The available options are:
OptionDescription
AutoThe software will automatically pick a marker for your data points. This is the default option.
CircleUse a circle for the marker for each data point.
SquareUse a square for the marker for each data point.
DiamondUse a diamond for the marker for each data point.
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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: Click on this button to save any changes and compute the analysis outputs if possible.

Data

If you click on the Data button, you will see the following dialog box. 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 to speed up finding the right data to use 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 does not have any 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 important 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 either to add more data into 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 up the Data Editor dialog box where you can import more data into your workbook, or you can 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, then you will need to select only numeric columns. If the code starts with a T, then you can select both 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, then you need to select a minimum of 2 columns of data and a maximum of 4 columns of data 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 select 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 select the data is to double click on the columns in the list of Available Data. Finally, you can also 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: If the right amount of data columns has been specified, the list box header will be displayed in the black color. If sufficient data has not been specified, then the list box header will be displayed in the 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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View Selection: Click on this button to view the data you have specified for this analysis. The data can be viewed either in a tablular format or in a graphical summary.

Charts

If you click on the Charts button, you will see the following dialog box. Charts
1
Title: The system will automatically pick a title for your chart. However, if you would like to override that with your own title you can specify a title for your chart here. Note that this input is optional.
2
Sub Title: The system will automatically pick a subtitle for your chart. However, if you would like to override that with your own subtitle you can specify a subtitle for your chart here. Note that this input is optional.
3
X Label: The system will automatically pick a label for the x-axis. However, if you would like to override that with your own label for the x-axis you can specify a different label here. Note that this input is optional.
4
Y Label: The system will automatically pick a label for the y-axis. However, if you would like to override that with your own label for the y-axis you can specify a different label here. Note that this input is optional.
5
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 then 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 the x-axis increment is set at 2. Note that this input is optional.
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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 then the minimum y-axis scale is set at 10 and the maximum y-axis scale 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: If you want to add a few extra horizontal reference lines on top of your chart you can specify the values here. The format for this input is numeric values separated by semi-colon. For example, if you specify 12;15 then two horizontal lines are plotted at Y = 12 and Y = 15 respectively. Note that this input is optional.
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Vertical Lines: If you want to add a few extra vertical reference lines on top of your chart you can specify the values here. The format for this input is numeric values separated by semi-colon. For example, if you specify 2;5 then two vertical lines are plotted at X = 2 and X = 5 respectively. Note that this input is optional.

Verify

If you click on the Verify button, the software will perform some checks on the data you have entered. A sample screenshot of the dialog box is shown in the figure below. Verify The objective of this analysis as well as any checks that are performed is listed in this dialog box. For example, the software may check 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, then they are shown as a green-colored checkmark. If the verification checks fail, then they are shown as a red-colored cross. If the verification checks result in a warning, they are shown in the orange color exclamation mark and finally, any checks that are required to be performed by the user are shown as blue info icons.

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. It contains a summary of number of rows of data, any skipped rows, and the number of distinct groups. The analysis results section contains the following information for each group: group name, number of data points within the group, the minimum, mean, and maximum values for the x data points, the minimum, mean, and average values for the y data points.

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Graphs: The graph section contains the scatter plot. The scatter plot indicates if we have a positive, negative, or no relationship. If all the data points fall along a straight line with the line sloping upwards, then we say it has a positive relationship. If the line is sloping downwards, then we say that it has a negative relationship. If there is no line or the best possible line is horizontal, then we say that there is no relationship between x data and y data points.

Notes

Here are a few pointers regarding this analysis:
  • You can use the standard Excel functions to format the graph. However, note that if you click on Compute Outputs again you may lose all the formatting that you have done to your graph.
  • Right mouse click on the trendline to change the equation used to generate the trendlines.

Examples

Following examples can be found in the Examples folder.
  • Create a scatter plot for the advertising spend vs. sales revenue for the data given in the reference file. (Scatter Plot 1.xlsm).