Math 10B - Algebra II

Wednesday, October 26, 2016

Linear Regression or "Line of Best Fit"

Homework due Thursday:  pg. 44 # 19, 22, 25 
                                            pg. 46 # 26, 30, 31, 34

Quiz 1.3 on Friday

Line of Best Fit on a TI-Nspire:

To enter data (x and y values)  in to the calculator:

        Start at “Home”, press [new document], save and name it. (starts with page 1.1)

To create a Line of Best Fit:

Step 1:
  a) Press [menu] add Lists and Spreadsheets.
              b) At the top of the first column enter a name (you pick the name) for your x-variable
              c) At the top of the second column enter a name (you pick the name) for your y-variable.
              d) Enter the x-values (1 value in a box) under the first column

              e) Enter the y-values (1 vaue in a box) under the second column

Step 3. Press [menu], press [ 4 statistics], press [1 stat calculations], press [3 linear regression mx+b]

Step 4. See the pop-up menu:  
              a)  For X-list: Press [►] until you select the name of your first column then press [tab]
              b)  For Y-list: Press [►] until you select the name of your second column then press [tab]
              c) Press [Enter] or press [OK]

To create a scatter plot:  

Step 1:  a)  Press [CTRL], press [DOC] to add a page to your document.  (page 1.2) 
              b)  Press Data & Statistics, press [enter] 

Step 2:  a) Move curser to bottom center of graph paper and click on the box that appears,
              b) Choose the title you created for x- variables. 
              c) Move curser to left center of graph paper and click on the box that appears,   
              d) Choose the title you created for y-variables. 

To graph the Line of Best Fit on the scatter plot: 



                Press [menu], press [analyze], press [regression], choose Linear Regression (y=mx+b).


Note: Remember "r" is the "correlation coefficient" that ranges between -1 and +1. It tells us how well our data points fit the line. The closer "r" is to -1 or 1 means the closer the data points are to our Line of Best Fit.


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