Graphing with Excel. Mr. Heinrich/Mr. Flock R.O.W.V.A. High School, Oneida, IL Physics 4B

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1 Graphing with Excel Mr. Heinrich/Mr. Flock R.O.W.V.A. High School, Oneida, IL Physics 4B For almost any project that requires the analysis and manipulation of data sets, the standard is Microsoft Office Excel. There are a number of spreadsheet programs available which provide the same basic functions but Excel is by far the most widespread. A number of careers frequently utilize the powerful tools provided by a spreadsheet. Whether you want to be an architect, engineer, actuary, physicist, chemist, psychologist, or any number of careers that require repeated calculations of data, Excel will be a daily tool in most cases. Hence it is important for you to learn to use Excel to perform complex calculations and data manipulations that would be otherwise tedious or difficult. Excel is simply a software program which executes a series of commands to produce data tables and charts. Learning to use Excel is like learning another language; once you know the proper vocabulary and grammar rules it will become second nature to you. And just like learning a language it is important to practice and experiment. This sheet is designed to guide you through the steps of making a simple XY scatter plot. It outlines the basic steps to produce a plot that can be used to draw conclusions. Of course more advanced techniques can be learned, if there is something you want to do, it can probably be done just ask! Step #1-Data Record your raw data into columns, heading each column with a label that is clear and includes the units of the measurement. DO NOT include the units with each data point, Excel will not recognize g, s, m, etc as a data point and will not properly interpret the numbers. Step #2-Selecting Data Select the data you want to graph. Select the independent variable first, followed by the dependent variable. If the two columns of data are separated, hold down the control key to select the second column.

2 Press and hold the Control Key (Command Key for Macs) to select a second column while keeping another column still selected (on right). Step #3-Creating a Chart With your two columns selected click the Chart Wizard button in the toolbar or under the Insert drop down menu choose Chart

3 The Chart Wizard will open and give you a variety of charts to choose from. In this class you will almost exclusively use XY Scatter Plot, however there maybe some instances where you use something else and it is important to understand which chart type you want given the data you have collected. Click Next. Select the Series tab at the top of the Chart Wizard. Make sure that you have the correct data column in the X Values (the independent variable) and the Y Values dependent variable. You may need to do this with each Series (data set) you include. Click Next

4 Type in clear and concise titles and labels for the axes, making sure to include the units of measurement for both axes. Under the Gridlines Tab, add Major Gridlines to the X Axis. Under the Legend Tab, either select or deselect the Show Legend checkbox depending on whether or not a legend is necessary. If you are displaying more than one data set, the legend is necessary. Click Next.

5 Place the chart in a new sheet using the radio button. If you want, you can rename the sheet to make it easier to find. Click Finish. Step #4-Formatting your Chart First remove the grey area from the background of the chart. You can do this by right clicking on the plot area (not the gridlines or data points). Choose Format Plot Area From the menu that comes up choose Color: No Fill

6 If necessary, format the axis and adjust the scale by right clicking on the axis and selecting Format Axis In the menu the comes up, select the Scale tab and manually adjust the scale if necessary. Excel will spread your data out over a range which maximizes the view of the data points. However, sometimes this is deceiving and it is more useful to extend the scale to produce a more intuitive plot. This is something you will have to decide for each plot.

7 Finally you will want to add a trendline to determine a mathematical relationship between your independent and dependent variables. Select the data set by clicking on one of the data points. Then either right click on the data point or choose Add Trendline from the Chart drop down menu. Then choose and appropriate type of trendline equation (i.e. linear, exponential, etc.)

8 Choose the Options Tab and check both the Display equation box and the Display R-squared value box. Then click OK You can also change the name of the trendline as it appears in the legend. Your final chart should look something like the picture below and is now ready to be printed or used for further data analysis. Don t forget to save the Excel workbook somewhere where you can reference it if you need to make changes or print another copy.