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The observed value combinations (x,y) for 5 data sets are: (6,6), (11,9), (15,12), (21,17), (27,16). Which statement correctly describes the correlation coefficient result for this sample data?
A. Indicates a low degree positive linear relationship between x and y
B. Indicates a moderate degree positive linear relationship between x and y
C. Indicates a high degree positive linear relationship between x and y
D. Indicates a high degree negative linear relationship between x and y
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Coefficient > 0 means positive correlation. Coefficient very close to 1 indicates very strong positive correlation.

要確定這些數(shù)據(jù)點(diǎn)的相關(guān)系數(shù),我們需要計(jì)算皮爾遜相關(guān)系數(shù)(Pearson correlation coefficient)。皮爾遜相關(guān)系數(shù)的公式為:

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

首先我們計(jì)算各項(xiàng)的值:

給定數(shù)據(jù)點(diǎn):(6, 6), (11, 9), (15, 12), (21, 17), (27, 16)

1. 計(jì)算各個(gè)數(shù)據(jù)的和:
\[ \sum x = 6 + 11 + 15 + 21 + 27 = 80 \]
\[ \sum y = 6 + 9 + 12 + 17 + 16 = 60 \]

2. 計(jì)算各個(gè)數(shù)據(jù)的平方和:
\[ \sum x^2 = 6^2 + 11^2 + 15^2 + 21^2 + 27^2 = 36 + 121 + 225 + 441 + 729 = 1552 \]
\[ \sum y^2 = 6^2 + 9^2 + 12^2 + 17^2 + 16^2 = 36 + 81 + 144 + 289 + 256 = 806 \]

3. 計(jì)算各個(gè)數(shù)據(jù)的乘積和:
\[ \sum xy = (6 \times 6) + (11 \times 9) + (15 \times 12) + (21 \times 17) + (27 \times 16) = 36 + 99 + 180 + 357 + 432 = 1104 \]

將這些值代入皮爾遜相關(guān)系數(shù)公式:

\[ r = \frac{5(1104) - (80)(60)}{\sqrt{[5 \times 1552 - 80^2][5 \times 806 - 60^2]}} \]
\[ r = \frac{5520 - 4800}{\sqrt{[7760 - 6400][4030 - 3600]}} \]
\[ r = \frac{720}{\sqrt{1360 \times 430}} \]
\[ r = \frac{720}{\sqrt{584800}} \]
\[ r = \frac{720}{764.80} \approx 0.94 \]

相關(guān)系數(shù) \( r \approx 0.94 \) 表明 \( x \) 和 \( y \) 之間有很高的正線性關(guān)系。因此,正確答案是:

C: 表示 \( x \) 和 \( y \) 之間有高度正線性關(guān)系。