Question

For the following data

x y

Mean 65 67

Standard deviation 5.0 2.5

Correlation coefficient 0.8

Then the equation of line of regression of y on x is

• A. $y - 67 = \frac{2}{5}(x - 65)$
• B. $y - 67 = \frac{1}{5}(x - 65)$
• C. $x - 65 = \frac{2}{5}(y - 67)$
• D. $x - 65 = \frac{1}{5}(y - 67)$

Answer 1

Answer: (A)

$y - 67 = \frac{2}{5}(x - 65)$

Answer 2

Since the line of regression of y on x is

$y - \bar{y} = r.\frac{\sigma_{y}}{\sigma_{x}}(x - \bar{x})$ ⇒ $y - 67 = \frac{0.8 \times 2.5}{5}(x - 65)$

⇒ $\overline{x_{1}} = \frac{nM - a}{4}$.