I'm a bit lost on the simple linear regression topic...how can i find the equation of the straight line that best fits the following data
Age (x)
40
20
32
15
33
8
26
18
27
48
12
Salary (y)
70
93
87
102
72.8
125
86
94.4
90
61.2
109
Thank in advance!
If you are knowledgeable/confident enough in Micro$oft Excel (or the essentially equivalent free version of Excel: Open Office Calc), you should find the task of entering your data and producing linear equation quite easy. However, there are other alternatives. You could get the free TRIAL for Data Desk, which last forever as I recall, but limits features such as saving, copying, pasting, etc your data sessions. Alternatively, you could download the free TRIAL for JMP, although this package (perhaps like Data Desk) has a learning curve. The trial runs out after 30 days, and then (unless you want to pay a king's ransom to use it for the rest of your life) you should uninstall it immediately as it is a HUGE file.
Finally, this is what I would opt to do: Use this remarkable tool called Google. Enter in the search query "Linear Regression Applet". Then about 4 or 5 results down, (and I chose one at random), you may find something such as Linear Regression and Correlation Script
You can copy and paste your x-values and y-values (coordinates), hit enter (or the button at the bottom "Calculate." I even did it. What did I get? A sketch of the graph with numbered/labeled axes, the calculated slope with error values, y-intercept with error values, correlation coefficient, chi-square and degrees of freedom, and a whole bunch of other goodies you probably wont need, yet are certainly germane to your assignment. In fact, the lines on the sketch are color coded as well.
Bookmark the site! Or find one of the other billions that you like better and bookmark it! Always try Google for simpler tasks fellas. It's magic.
Take care,
-Andy
Good suggestion, Andy. I didn't know about that site and it is very nice. I especially like the fact a user does not have to download an applet (Flash or Java).
Just out of curiousity, I took your advice and did a Google search using the term "Linear Regression Applet". Most of the search results are, indeed, applets, that require a download. However, I would like to recommend another applet (written in Javascript) that does not require downloading anything (although it does not draw a graph):
Polynomial Regression Tool