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If for 25 observations of pairs (x,y), S...

If for 25 observations of pairs (x,y), `Sigmax=200,Sigmay=150,Sigmax^(2)=3000 and Sigmaxy=1500` then the equation of line of regression of y on x is

A

`A) 3x+14y=60`

B

B) `3x-14y+60=0`

C

`C) 14x-3y=60`

D

`D) 3x-14y=60`

Text Solution

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The correct Answer is:
To find the equation of the line of regression of \( y \) on \( x \) given the data, we will follow these steps: ### Step 1: Identify the given values We have the following values: - Number of observations, \( n = 25 \) - \( \Sigma x = 200 \) - \( \Sigma y = 150 \) - \( \Sigma x^2 = 3000 \) - \( \Sigma xy = 1500 \) ### Step 2: Calculate the means \( \bar{x} \) and \( \bar{y} \) The means are calculated as follows: \[ \bar{x} = \frac{\Sigma x}{n} = \frac{200}{25} = 8 \] \[ \bar{y} = \frac{\Sigma y}{n} = \frac{150}{25} = 6 \] ### Step 3: Calculate the slope \( b_{yx} \) The formula for the slope \( b_{yx} \) of the regression line of \( y \) on \( x \) is: \[ b_{yx} = \frac{\Sigma xy - n \cdot \bar{x} \cdot \bar{y}}{\Sigma x^2 - n \cdot \bar{x}^2} \] Substituting the known values: \[ b_{yx} = \frac{1500 - 25 \cdot 8 \cdot 6}{3000 - 25 \cdot 8^2} \] Calculating the terms: \[ = \frac{1500 - 1200}{3000 - 1600} \] \[ = \frac{300}{1400} = \frac{3}{14} \] ### Step 4: Write the equation of the regression line The equation of the regression line can be expressed as: \[ y - \bar{y} = b_{yx}(x - \bar{x}) \] Substituting the values of \( \bar{y} \), \( b_{yx} \), and \( \bar{x} \): \[ y - 6 = \frac{3}{14}(x - 8) \] ### Step 5: Rearranging the equation Multiplying through by 14 to eliminate the fraction: \[ 14(y - 6) = 3(x - 8) \] Expanding both sides: \[ 14y - 84 = 3x - 24 \] Rearranging gives: \[ 3x - 14y + 60 = 0 \] ### Final Answer Thus, the equation of the line of regression of \( y \) on \( x \) is: \[ 3x - 14y + 60 = 0 \] ---
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