1. Consult an almanac, newspaper, magazine, or the Internet to find data that appear to lie approximately on or near a straight line. A few of the many free sources of data that might be appropriate to use are:
2. Create a scatterplot and a line fitting the data in one of two ways:
a. To do this activity by hand, create a scatterplot by plotting the (x, y) data in a Cartesian (rectangular) coordinate system. Then, draw a line that approximately fits the data in the scatterplot, and then write its equation as a function in slope-intercept form. An easier way, and one that produces better looking results, is to find the equation of the line for your data using this free, online linear regression calculator: http://www.alcula.com/calculators/statistics/linear-regression/.
b. To use the regression calculator:
- Enter your data, but without parentheses ( ), in the empty data field at: http://www.alcula.com/calculators/statistics/linear-regression/. For example, for my first point, I would type 1,5 not the usual ordered pair format of (1, 5).
- When all of your data points are entered, click on the “Submit Data” button. The line of best fit y = mx + b for your data will be displayed, as will a figure showing a scatterplotof your data and the graph of your line of best fit.
- Right-click on the displayed figure of the scatterplot/graph and save it to your computer. Then, load it into the discussion box when you make your post. To do that, click on the image button in the palette of the discussion text-editor window. In that menu, you load the figure from your computer into your post.
3. Also include a link to your data, along with an explanation of what the x and y axes represent in your graph.
To gain full credit for your work, you must complete all the directions.