I.T. Skills
Graphs, Lines of Best Fit, Equations

1. Introduction

1.1 Why use a computer to draw graphs?

Using a computer is not necessary, will not gain you any more marks, and will probably take you longer than hand drawing a graph. So what are the advantages? If you persevere you will be able to produce a graph which is as good as a hand drawn graph. If you take care with entering your data then you can eliminate silly calculation and plotting mistakes. The final image can be tweaked and adjusted, simple mistakes can be corrected, and the graph easily reprinted. With enough practice you can probably set up a graph template and be able to produce graphs almost as quickly as by hand drawing them. (As long as you have access to a computer, with a printer, and both are working well.) In the long run there are advantages and the graph generating skills may be useful for other things than your science coursework. If you are prepared to go one step further then you can use more advanced features to try out lines of best fit and automatically generate the equation for the line. If you are confident with your mathematical skills then this shouldn't be too much of a problem.

1.2 The Options

There are many different software packages for creating graphs and lines of best fit. If you already have one on your computer then use that. Details for two packages are given here. The first, Microsoft Excel, is in common use but is complex and difficult to master. The second package you will probably not have heard of before. It is a dedicated graph drawing and line of best fit program that is available as Shareware. It is very easy to use and is a no frills package, the main advantage being that you can easily download it from the internet. There are many similar programs to this if you search the Shareware web sites.

At the end of the day, so long as the program can produce a good graph, it doesn't matter which one you use. What I suggest you do is look at the example graphs and make sure that you can produce yours to the same standard.

2. Microsoft Excel

Excel Tutorial - Graphs and Lines of Best Fit

How to:

• Format the data table
• Calculate averages
• Create a line graph
• Add a line of best fit
• Show the equation for the line

3. Equation Grapher with Regression Analyzer v3.2

Regression Analyzer 3.2. Tutorial - Graphs and lines of Best Fit

There are two programs, the Regression Analyzer is the one you need to use for plotting graphs and finding lines of best fit. The Equation Grapher draws graphs for mathematical equations - this part could come in handy for maths work.

You can find out more details and download the program from the mfsoft web site:
www.mfsoft.com

4. Word Processing Maths Symbols

4.1 The problem

Your computer keyboard has the letters of the alphabet, numbers, punctuation marks and some symbols. When it comes to science and maths symbols in particular what do you do? If you are using a good word processor it will allow you to insert all sorts of symbols and characters. Most simple equations can be entered quite easily, more complicated equations may require a bit more planning. It is possible to leave a space and write the equations in by hand. There is nothing wrong with doing this provided you do remember to write them in!

4.2 Standard keyboard symbols

%	percent
( )	brackets
+	plus
-	minus
/	divide
X or x	multiply
=	equal
<	less than
>	greater than

4.3 Superscripts and subscripts

A raised symbol is called a superscript. These are often used for writing squared and cubed symbols.
e.g. y = x²

A subscript is a lowered symbol.
e.g. average = (x₁ + x₂ + x₃)/3

These effects can be added by changing the font properties. With Microsoft Word you can do this by highlighting the number, and then choosing Format and Font. Use the help feature of your word processor to find out how to do the same thing.

4.4 Other symbols

With Microsoft Word choosing Insert and then Symbol will display a whole range of additional symbols that can be inserted. Other word processors have similar features. By changing the selected font even more symbols become available. The symbol and normal fonts provide most of the special symbols that you should need.

Selected additional symbols

÷	division
×	multiplication
√	square root
°	degree symbol
¼ ½ ¾	fractions
² ³	squared and cubed
β γ δ α ι ρ	Greek letters
∝	proportional sign
∞	infinity sign
→ ⇒	arrows

Symbol character set

4.5 Example equations

Kinetic energy

E_k = ½mv²

Aerobic respiration

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

5. Microsoft Equation Editor 3.0

5.1 Creating Equations with Microsoft Word

If you use Microsoft Word it has an equation editor that will cope with most simple equations. It's not too obvious how to start the equation editor but once opened it is very easy to use. If you didn't install the complete Microsoft Word package you may be prompted to insert the installation disk the first time you try to use the Equation Editor.

Inserting an Equation

Place the cursor at the position in the document where you would like to insert the equation.

From the main menu select the following:
Insert then Object...
In the Create New list double click Microsoft Equation 3.0.

The Equation Editor window should now open. The editor has a few basic menu commands and a floating toolbar containing the main equation elements you are likely to need. Simply type words and numbers from the keyboard in the normal way and use the toolbar to enter the correct equation symbols. When you've finished, click outside the equation to return to normal editing mode. If you want to change the equation simply double click it to start up the equation editor once again.

5.2 This is a screenshot of the editor.

Download the test file containing this example equation.

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