How to find the correlation coefficient (r) using your graphing calculator

[Pages:1]How to find the correlation coefficient (r) using your graphing calculator

1. Create your scatterplot 2. Plot it on the coordinate plane and decide which regression model (see

pg. 145 in your textbook) that best fits the data 3. Press: Stat; Calc and pick the regression model 4. "r" should be listed with the equation 5. IF you have a TI-84 and the screen looked like this:

LinReg

y = ax + b

a = -2

b= 3

You need to turn your diagnostic on Press: 2nd, 0 to open catalog Press: x-1 to jump to the "D" section and scroll to "DiagnosticOn" Press: Enter twice and "Done" will appear

Start at Step 3 again, and "r" will appear this time.

Practice, using this data:

Weekly Sales Data based on Marketing

Research

Price Per Box

Boxes Sold

$2.40

38,320

$2.60

33,710

$2.80

28,280

$3.00

26,550

$3.20

25,530

$3.40

22,170

$3.60

18,260

You should pick a linear equation (option 4) y = -15358.92857x + 73622.5 r2 = .961441501 r = -.9805312341

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