The links listed below will guide you step-by-step through the listed processes for using Vernier's Graphical Analysis 2.0:
Analysis Tools Under the Analyze Menu
1. Examine:
This feature displays the values of each individual data point. To use this feature, click Analyze and choose Examine.

Move the cursor across the graph. A vertical line will be drawn through the data point nearest the cursor with an attached databox which shows the values for that point.

The Examine feature will remain active until you go back to the Analyze menu and deselect Examine. The check mark next to the feature indicates that it is active.

2. Integrate
This feature displays the integral. To use this feature, click and drag the mouse across a specific region of the graph and then click on Analyze and choose Integrate.
The area under the curve is shaded and the numerical values for this function are displayed under the x-axis. The trapezoid rule is used to find the approximate area under the curve for the selected data.

3. Regression Line
This feature is used to calculate the best fit line for a curve or region of the graph. To fit a regression line to your data set, click and drag the mouse across the graph and click on Graph then choose Regression Line.


A best fit line will be drawn on the graph.

This feature can be used with the entire data set or just a portion of it.

To add the Regression Statistics to the graph, click on Graph and then choose Regression Statistics.
The numerical values for the line will be added under the x-axis.

4. Automatic Curve Fit
This feature can be used to fit various mathematical equations to the data. To use this feature, click on Analyze and then choose Automatic Curve Fit.

The window to the right opens. I chose the first option which is Linear. Click OK.
The best fit Linear line is drawn through the data points. Is this the best fit line? Apparently not, but if in doubt look at the Mean Square Error in the lower left hand corner. This number should be small, if the fit is appropriate. Click on New Fit in the lower right hand corner.
The box to the right will open up. Choose Exp this time.
This is the result of choosing Exponential. As you can see, this is the best fit line for this data set. Notice the Mean Square Error and compare it to the Mean Square Error on the linear curve fit graph.

5. Manual Curve Fit:
Click on Analyze, then Manual Curve Fit.......
A custom equation can be entered by placing your cursor in the box next to f(x) = . This function requires you to enter the coefficients, constants, and exponents for the chosen model. The program will determine the curve fit by trial and error as it tries various values.

2. Statistics:
This option allows you to determine statistical information about selected data in the data table. It provides the minimum, maximum, mean, and standard deviation for the area selected.

Select the first column of data on the data table.

Click on Data and then choose Statistics.

A data box will be displayed on the screen that lists the statistics for the data set selected.

Creating a New Column of Data to Determine Relationships Between Variables

We are going to use BOYLE.dat file supplied with this program to add a new calculated column to the data set.

1. Open the Graphical Analysis program and open BOYLE.dat which shows the relationship between pressure and volume.

1. Highlight the Volume column of data.

 

2. Click on Data, Column Formula then choose Ln.

 

 

 

3. This enters the linear value for the volume value in the new column.

4. To graph the new column of data, click on the x-axis and choose =Ln (Volume). The image below shows the resulting graph.

Additional choices are available under Column Formula and include:

  • Raise to a Power
  • Exp
  • Log
  • Sine
  • Cosine
  • Tangent
  • Plus a Constant
  • Times a Constant
  • Delta
Sample Data Files

There are a number of sample data files which are available with the Graphical Analysis program to use as tools to find relationships between variables. There is a complete list in your Graphical Analysis manual on page 26. Boyle.dat is just one example of the sample data files available.

1. Coulomb.dat shows the relationship between distance and electrical force.

2. Decay.dat shows the decay rate of a radioactive sample.

3. Freefall.dat shows the speed and time of a free falling golf ball.

4. Galileo.dat shows the distance traveled from rest for a ball rolling down an inclined plane.

5. Postal1.dat shows the cost of mailing a letter from 1958-1982.

Printing Options
1. Click on the title bar of the data table to select it. Then click on File, Print Data Set. This option will print the entire table including the rows not displayed in the window.
2. Click on the title bar of the graph to select it. Then click on File, Print Graph.
3. Choose File, Print Screen. This option will print the entire screen.

4. The Printer Options selection allows you to include a header that is visible when the document is printed. Information can include Name, Date, and Page Numbers.

©2000-2002 April A Cleveland for Science Junction, NC State University.
All rights reserved.
URL: http://www.ncsu.edu/sciencejunction/route/usetech/dataanalysis/macdataanalysis/gaanalyzedata/index.html
Last updated 07/30/02

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