Scatter plot and best fit line
Task
Create a Scatter Plot and conduct a Two Variable Regression Analysis for a given data set to explore how outliers affect the best fit line.
Explore the construction...
Instructions
1. | | In the Spreadsheet View, enter the following data values into the cells of column A: A1: 1 A2: 5 A3: 2 A4: 8 A5: -2 |
Hint: Always evaluate your input by hitting the Enter key. | ||
2. | | Enter the following numbers into the spreadsheet cells of column B: B1: -1 B2: 2 B3: 3 B4: 4 B5: 1 |
3. | ![]() | Create a Scatter Plot from this data: Highlight all cells of columns A and B that contain data. Then, select the tool List of Points from the Spreadsheet View Toolbar and click Create to create points from your data set. |
Note: The values in column A determine the x-coordinates and the values in column B specify the y-coordinates of the plotted points. | ||
| ![]() | Hint: You might want to use the Move Graphics View tool if not all five points are visible in the ![]() |
4. | ![]() | Select the Best Fit Line tool from the Graphics View Toolbar. Create the line that best fits your data points by using a selection rectangle that contains all data points plotted. |
Hint: Create a selection rectangle by clicking in the upper left corner of the Graphics View and dragging down to the lower right corner of the ![]() | ||
5. | ![]() | Exploration: Using this construction you can easily demonstrate how outliers affect the best fit line of a data set. Select the Move tool and drag one of the points to create an outlier. |
Hint: You can also change the initial data directly in the ![]() |