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3 years ago

What is the correlation coefficient with the following data points: (15,36), (13,22), (12,6), (11,20)?

Mathematics

1 answer:

Rina8888 [55]3 years ago

6 0

Answer:

A. 0.75

Step-by-step explanation:

The formula for the correlation coefficient r is

$r =\frac {n \sum{xy} - \sum{x}\sum{y}}{\sqrt{[n \sum{x^{2}}- (\sum{x})^{2}}][n \sum{y^{2}}- (\sum{y})^{2}]}$

It's easier to use a statistical calculator, but this question probably expects you to do it by hand.

Let’s write a table for easy calculation.

x y xy x² y²

15 36 540 225 1296

13 22 286 169 484

12 6 72 144 36

11 20 220 121 400

51 84 1118 659 2216

(Σx)² = 2601

(Σy)² = 7056

$r =\frac{4\times1118-51\times84}{\sqrt{[4\times659-2601][4\times2216-7056]}}$

$r =\frac{4472-4284}{\sqrt{[2636-2601][8864-7056]}}$

$r =\frac{188}{\sqrt{35\times1808}}$

$r =\frac{188}{\sqrt{63280}}$

$r =\frac{188}{251.6}$

r = 0.747

The graph below shows that there is a poor correlation among the points.

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Step-by-step explanation:

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3 years ago

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3 years ago

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Step-by-step explanation:

There are 2 items that need to be checked.

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The diameter of the coordinates is the diameter of the circle.

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Check:

Graph to confirm your answers are correct (see attached)

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