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

2. Tangent Line
This tool displays the tangent line. To use this feature, move across the graph and a tangent line will be drawn at each data point. An attached data box displays the numerical value of each point.

3. Integrate
This tool displays the integral. To use this feature, click and drag the mouse across a specific region of the graph and click the Integrate button. The area under the curve is shaded and a data box displays the numerical values for this function. The trapezoid rule is used to find the approximate area under the curve for the selected data. Note: The direction in which you drag the mouse effects whether the integral is positive or negative.
From left to right = positive
From right to left = negative

4. Regression Line
This tool 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 mouse across the graph and click the Regression Line button. A best fit line will be drawn on the graph and a data box will display the numerical values for the line. This tool can be used with the entire data set or just a portion of it.


5. Automatic Curve Fit
This tool can be used to fit various mathematical equations to the data. When this button is clicked, 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 right hand corner. This number should be small, if the fit is appropriate. So click New Fit and try another equation to find the best fit line.
This is the result of choosing Exponential. As you can see, this is the best fit line for this data set.
Click OK Keep Fit and a data box will be displayed showing the calculated coefficients, constants and/or exponents and the mean square error.
Options Under the Analyze Menu

1. Manual Curve Fit:
Click on Analyze, then Manual Curve Fit.......
A custom equation can be entered by placing your cursor in the box at the top of the Manual Curve Fitting window next to y =. 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 add statistical information to the graph. It provided the minimum, maximum, mean, and standard deviation for the area selected.

Select an area of the graph you want to analyze by holding down the left mouse button at the point you want to begin and move the mouse across to the point on the graph where you want to end your analysis.

Click on Analyze, the Statistics.

A box will be placed on your graph that contains the minimum, maximum, mean, and standard deviation for the area selected.

3. Floating Box Options:
Click on Analyze, then Floating Box Options......
This option can be used to change the appearance of data boxes associated with the graphs.

When the Line is visible is checked there is a line from the box to the graph. To make the line disappear, do not put a check in the box.

Box is visible: This checkbox controls whether the floating box is drawn on the graph. It is always selected when the current floating box belongs to an integral or regression line because their boxes can not be removed.

Delete: This button removes floating box and its graph element from the graph.

<<Prev and Next>>: These buttons allow you to select which floating box you want to modify. If there is only one floating box on the graph, these buttons will not be available.
Creating a New Column of Data to Determine Relationships Between Variables
This feature allows you to create a new column of data or calculate a new column of data from an existing file.

1. Click on Data, then New Column, then Manually-entered....
2. This box will appear where you can add a New Column Name and New Column Units.
3. Click on Data, then New Column, then Calculated...

4. The box to the left will appear in which you can add a name for the new column of data and units.

5. Move to the New Column Formula: and type in a formula or click on the calculator type buttons to provided.

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.

2. Click on Data, then New Column, then Calculated...

3. Enter Reciprocal Volume for the the New Column Name:

4. Enter Reciprocal ml for the New Column Units:

5. Place the cursor in the New Column Formula: box and click on the number 1 on the calculator keypad.

6. Click on the divide symbol. (/)

7. Click on the Columns drop down menu and choose volume. The New Column Formula: box should now read: 1/"Volume"

8. Click OK to save this new column of data.

 

9. To graph the data, position the mouse over the x-axis label. A box will appear around the label, click on it. The box to the left will appear. Click the radio button next to Reciprocal Volume.

10. The graph below is a result of this x-axis change.

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. Choose File, Print, Data Table. This option will print the entire table including the rows not displayed in the window.
2. Choose File, Print, Selected Display. This prints only the portion of the window displayed on the screen. This option can be used to print graphs, data tables and other windows, such as text windows. To print the graph area, click on the top of the graph and make the gray area blue. Then choose Selected Display under the Print menu. This also applies to the data table or text window. Click on the top of either one and change the gray area to blue. Then choose Selected Display under the Print Menu.
3. Choose File, Print, Whole Screen. This option will print the entire screen This will not print all the text in a text box with a scroll bar.
4. In order to print all the text, the text window must be selected and then Edit, Copy Text selected. The text can then be pasted into a word processor document and then the document can be printed.

5. The Printer Setup option allows you to include a header which can be visible when the document is printed. Information can include Name, Date, and Print Statistics with Data Tables.

©2000-2002 April A Cleveland for Science Junction, NC State University.
All rights reserved.
URL: http://www.ncsu.edu/sciencejunction/route/usetech/dataanalysis/pcdataanalysis/gaanalyzedata/index.html
Last updated 07/31/02

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