Activity 1.2.4: Student Resource Sheet
Determining the Equation of a Line Using Microsoft Excel:
The equations you have been working with to estimate height from bone have followed the general formula for an equation of a line:
y = mx + b
y = height of the person (in cm)
m = slope of the graph
x = length of the limb bone (in cm)
b = y intercept
To derive this equation, you can graph your data points by hand and extrapolate values for the slope and the y-intercept, or you can use data analysis software such as Microsoft Excel to estimate the line from your data. To graph your data and determine the equation of the line using Excel, follow the directions found below:
1. Open a new file in Microsoft Excel.
2. In the A column, type in the tibial lengths (MLTs) for each of your data points.
3. In the B column, type in the heights (in cm) for each of your data points.
4. Once you have typed in all of your data, highlight it by holding the mouse and dragging an arrow to form a box around your numbers.
5. From the Menu heading at the top of the page, click on “Insert” and select “Chart.” The standard type you will use to create your graph is the (XY) Scatter plot. Click on this option.
6. Select the chart subtype you wish to use. For our graph, we want the graph without lines connecting the dots. This is called a Scatter Graph. Once you have selected the graph, click on the “Next” button at the bottom of the screen.
7. You will now see a preview of your graph. The “Series in: Columns” should be selected. Click the “Next” button.
8. You now want to give your graph a title. Type the title you have selected in the “Chart Title” box.
9. Type in the title for the X-axis. Which information did you plot on the x-axis?
10. Type in the title for the Y-axis. Which information did you plot on the y-axis?
11. Once you have finished filling out the titles, click on the “Legend” tab and uncheck the “Show Legend” box.
12. Click on the “Next” button.
13. Place chart: as a new sheet.
14. Click on the “Finish” button.
15. You next need to make a “best fit” straight line through your data points. Right click on one of your points to open the menu. Select “Add Trend Line” and then select Linear trend/regression type. You would also like to display the equation for your trend line. Click on “Options” and then click on “Display Equation on Chart.” Click OK.
16. Use the equation of the line to estimate height using tibial lengths.
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Human Body Systems Activity 1.2.4 Student Resource Sheet – Page 1