Math Plane 

Project:

Using the given data set:

1) construct a basic spreadsheet

2) identify the best fit linear equation

3) plot the data set

4) sketch the best fit line in the scatterplot

Step by step Instructions and Illustrations:

Build a spreadsheet:

1: New Document

4: Add Lists & Spreadsheet

(spreadsheet opens up)

Enter values:

place input values in the first column (A)

place output values in the second column (B)

Label column A --- "x"

Label column B --- "y"

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Cool feature: Using the TI-nspire software, you can save images of your work!

It'll save a screenshot to your computer!

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To save the document:

1:file

5: save as

choose a name (EX:  "regression project")

save  (enter)

To find the least squares regression ("best fit line"):

"menu"

4: statistics

1: stat calculations

3: linear regression (ax + b)

(or, 4: linear regression (a + bx)

X: List  a[ ]

Y: List  b[ ]

Note to enter the vector brackets:  

"ctrl"     " ( "   

Then,  d[ ] will put the regression results in column D

"OK"

The output:

To plot the data points:

"doc"

4: Insert

4: Graphs

(opens a new page with graph)

"menu"

3: graph entry/edit

5: scatterplot

Enter the appropriate input/output lists:

x <--   "x" (column A in your spreadsheet)

y ,<--  "y" (column B in your spreadsheet)

"enter"

The output:

IMPORTANT:  to view the rest of the points, we need to zoom out!

"menu"

4: window/zoom

4: zoom out

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NOTE: if you'd like to 'undo' your work, click "ctrl"  "esc" to reverse your actions.

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To add the regression (best fit) line:

"menu"

3: graph entry/edit

2: equation

1: line

1: y = mx + b

(enter the a and b values from your spreadsheet)

y = [1.61194] x  + [.37313]

The output: the line appears through the scatterplot

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NOTE: to toggle between screens 1.1 and screen 1.2 press "ctrl" and use the left and right arrows on the keypad/mousepad

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Finally, to save your work,

doc

1:file

4: save

It's saved in "my documents"

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Math Comic #101 - "Linear Regression" (8-30-13)  (Click lower right to view)

More sketches at the weekly Webcomic Gallery

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"TI-Nspire CX Mini-tutorial: Linear Regression" (Video summary) presented by media4math.com