Question

Calculate the correlation coefficient, r, for the data below. Row chart ( (x )(y ) ) row chart ( ( -10 )( 2 ) ) row chart ( ( -8 )( -3 ) ) row chart ( ( -1 )( -15 ) ) row chart ( ( -4 )( -10 ) ) row chart ( ( -6 )( -6 ) ) row chart ( ( -7 )( -5 ) ) row chart ( ( -5 )( -8 ) ) row chart ( ( -3 )( -13 ) ) row chart ( ( -2 )( -14 ) ) row chart ( ( -9 )( -1 ) )

Answer 1

Answer:

The correlation coefficient is approximately -0.9949

Step-by-step explanation:

The given data is presented as follows;

$\begin{array}{lcl}x&&y\\-10&&2\\-8&&-3\\-1&&-15\\-4&&-10\\-6&&-6\\-7&&-5\\-5&&-8\\-3&&-13\\-2&&-14\\-9&&-1\end{array}$

The correlation coefficient, r is given as follows;

$r = \dfrac{\sum(x_i - \overline x) \cdot (y_i - \overline y)}{\sqrt{\sum (x_i- \overline x)^2\times \sum (y_i- \overline y)^2 } }$

From MS Excel, we have;

∑($x_i - \overline x$)·($y_i - \overline y$) = -155.5

∑($x_i - \overline x$)² = 82.5

∑($y_i - \overline y$)² = 296.1

Therefore, r = -155.5/(√(82.5 × 296.1)) ≈ -0.9949

The correlation coefficient, r ≈ -0.9949