StatGraphics Plus Tutorial
WELCOME TO THE STATGRAPHICS PLUS FOR WINDOWS VERSION 3 DEMO. Parts of this write-up are from a WWW demo which Statgraphics uses for marketing STATGRAPHICS for WINDOWS.
STATGRAPHICS Plus is an easy-to-learn, easy-to-use PC-based statistics software package with an intuitive design that will make your everyday data analysis easier than you ever imagined.
This program is a working version of STATGRAPHICS Plus Version 3 that offers features of the base system, QualityControl, Design of Experiments, Time-Series Analysis, Advanced Multivariate Methods, and Advanced Regression Models modules.
GETTING AROUND STATGRAPHICS PLUS
When you enter STATGRAPHICS Plus, it displays an untitled data icon, a StatAdvisor icon, a StatGallery icon, and an untitled Comments icon. When you are ready to start working, you can either enter new data or use an existing file. The existing files can be either Statgraphics files, spreadsheets (EXCEL) or data files from other software packages. For our class we will restrict our data files to either Statgraphics file (SF or SF3 extensions) or EXCEL files (XLS extensions). [The Statgraphics software and manuals mention Statfolios, but to keep things simple at the outset, we will ignore Statfolios from our discussion].
EXAMPLES
We now present a number of examples. It is assumed that you have downloaded and inflated the data files from Dr. Hopfe's WWW page. The disk you downloaded the files to will be referred to as the data disk. For these examples, insert your data disk in the A: or B: drive.
EXAMPLE 1. Opening an existing Statgraphics data file, generating descriptive statistics and printing out the generated statistics.
For this example we will be obtaining descriptive statistics from a data file, CARDATA.SF, which contains 154 observations for cars. In particular we will be getting statistics about the random variable MPG, which represents the miles per gallon of gasoline. Note that CARDATA.SF is a Statgraphics file.
Make sure your data disk is in either the A: or B: drive.
To Open the Data File:
Select File...Open...Open Data File from the menu bar or click the Open Data File button on the system toolbar.
Helpful Hint: For a description of the buttons on the system and analysis toolbars, simply place the cursor on the button and a description of the button appears just below the cursor.
Double-click on the Data file/folder. Double-click on cardata.sf from the scrolling list that appears below the File Name text box. The system opens the data file and displays the data icon with the file name (see the lower left corner of the screen).
To Generate the Descriptive Statistics
Select Describe……… Numeric Data…….. One Variable Analysis
Double click on mpg
Click the OK button to display the Analysis Summary.
Click on the Tabular Options button on the analysis toolbar to display the Tabular Options dialog box. Select one or as many options as you like. To follow our example, select Analysis Summary, Summary Statistics and Stem-and -Leaf display.
Click the OK button.
Helpful Hint: To see other options that are available for an analysis, click the right mouse button on the pane of that analysis and select Analysis Options...To maximize a pane, double-click on it; to minimize it, double-click again.
Click the Graphics Options button on the analysis toolbar. The system displays the Graphical Options dialog box. Select one or as many options as you like. To follow our example, select Frequent Histogram.
Click on the OK button.
After reviewing the results, click the Minimize button to shrink the window to an icon.
To print the output, proceed like you would with any Windows package
Go to the main tool bar and select File ….. Print…. And pick the options you want. For our example select "all panes". Click the Ok button.
EXAMPLE 2. Opening an EXCEL file.
Rather than provide you with an EXCEL file, you will create an EXCEL file that you will later open up as a data file in Statgraphics for Windows.
Enter the following, in an EXCEL spreadsheet, where mpg is in cell A1.
mpg
24
34
45
36
43
34
24
14
31
33
35
38
Save the spreadsheet as an EXCEL 4.0 WORKSHEET titled CAR.XLS on your data disk.
When the above information is read in as data to Statgraphics for Windows, mpg will represent the name of the variable.
Make sure your data disk is in either the A: or B: drive.
To Open the Data File:
1. Select File...Open...Open Data File from the menu bar or click the Open Data File button on the system toolbar.
2. Now just select the file CAR.XLS.
The data is now ready for analysis!!
EXAMPLE 3. Creating a horizontal time series graph, which can then be inserted into a WORD document.
In order to do this example your WORD setup must include the graphics filters to insert a metafile. When MS Office is installed there are different levels of installation. If you do not have the full installation, you probably do not have the appropriate graphics filters. If this is the case, I suggest you use one of the computers in the BUS lab (BUS 1006-08) for inserting the graphs.
On the data disk there is a file called, TSDATA.SF. This Statgraphics file contains a variable bubbly, which represent monthly champagne sales for a firm. We will create a horizontal time series plot for bubbly and then import (insert) it into a WORD document.
Select File...Open...Open Data File from the menu bar or click the Open Data File button on the system toolbar. Select the field TSDATA.SF
From the main toolbar
Select SPECIAL…..TIME SERIES ANALYSIS……DESCRIPTIVE METHODS
Then click on bubbly.
Click on the OK button.
On the analysis toolbar, click on the graphics icon. There are a number of options. For our example, select Horizontal Time Sequence Plot.
Click on the OK button.
To maximize the plot, double click on it.
Printing the Plot
If you want to print the plot by itself, just proceed as you would with any Windows product. I.e. File…..Print….
If you want to insert the plot into a WORD document proceed as follows
If you do not have a color printer, we recommend you first convert the graph to a black and white graph. To do this. Go to the main tool bar (top) and select WINDOW….GRAPHICS….OPTIONS and check "Always Black and White". Then Click the OK button.
Now to save the graph so it can be imported into a WORD document, select FILE….Save Graph (note this is not just save, but save graph). Note the graph will be saved as a Windows Metafile (*.wmf). Provide a name and storage location. We suggest as an example, A:BUBPLOT
Go into the WORD document where you want to insert the graph and select INSERT….PICTURE…FROM FILE. The double click on the file (BUBPLOT). To resize the inserted plot, one can double click on the inserted plot and then resize it using the mouse cursor.
Print WORD document as you would any other WORD document.
EXAMPLE 4. X-BAR AND R CHART AND STATGALLERY
In this example you will set up an X-bar and R chart
To Open a Data File:
1. Select File...Open...Open Data File from the menu bar or click the Open Data File button on the system toolbar.
2. Double-click on qcdata.sf from the scrolling list that appears below the File Name text box. The system opens the data file and displays the data icon with the file name.
To Perform an X-bar and R Chart:
1. Select Special...Quality Control...Variables Control Charts...X-bar and R from the menu bar. The system displays the X-bar and R Charts data input dialog box.
2. Double click on cereal.
3. Click on the Subgroup Numbers or Size text box and type 5.
4. Click the OK button. The system displays the initial analysis window.
5. Click the Tabular Options button on the analysis toolbar to display the Tabular Options dialog box. To follow our example, select All.
6. Click the OK button.
7. Click the Graphics Options button on the analysis toolbar to display the Graphical Options dialog box. Select one or as many options as you like. To follow our example, select X-bar Chart, Range Chart, and Tolerance Chart.
8. Click the OK button.
Helpful Hint: To exclude a subgroup from an analysis, double-click the X-bar Chart to maximize the window. Click the point that is below the lower control limit (Subgroup 20). Click the Exclude/Include button on the analysis toolbar. The system excludes the point from the analysis, replots the charts, and recalculates all of the tabular options.
USING STATADVISOR
StatAdvisor is an exclusive feature of STATGRAPHICS Plus. It is a tool that allows you to display and print a short, easy-to-understand interpretation of an analysis.
StatAdvisor is available for use with most statistical analyses.
The interpretation includes a simple explanation of the results, which are data sensitive; that is, the interpretation varies according to the variables you use in the analysis. For example, when you use StatAdvisor after you perform a Multiple Regression analysis, the interpretation indicates which variables appear to add significantly to the fitted model.
You can access StatAdvisor by:
- clicking the StatAdvisor icon on the application window
- clicking the StatAdvisor button on the application toolbar
- selecting Help...The StatAdvisor... from the menu bar.