Correlation and RegressionMCQMTP June 22Question 3754 of 188
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Consider the two regression lines 3x+2y=26\displaystyle 3x + 2y = 26 & 6x+y=31\displaystyle 6x + y = 31. Find the mean values of x\displaystyle x and y\displaystyle y.

Options

Axˉ=4\displaystyle \bar{x} = 4 and yˉ=7\displaystyle \bar{y} = 7
Bxˉ=5\displaystyle \bar{x} = 5 and yˉ=6\displaystyle \bar{y} = 6
Cxˉ=6\displaystyle \bar{x} = 6 and yˉ=4\displaystyle \bar{y} = 4
DNone of these
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Correct Answer

Option axˉ=4\displaystyle \bar{x} = 4 and yˉ=7\displaystyle \bar{y} = 7

All Options:

  • Axˉ=4\displaystyle \bar{x} = 4 and yˉ=7\displaystyle \bar{y} = 7
  • Bxˉ=5\displaystyle \bar{x} = 5 and yˉ=6\displaystyle \bar{y} = 6
  • Cxˉ=6\displaystyle \bar{x} = 6 and yˉ=4\displaystyle \bar{y} = 4
  • DNone of these

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Detailed Solution & Explanation

The intersection point of the two regression lines gives the mean values of the variables, barx\displaystyle \\bar{x} and bary\displaystyle \\bar{y}. Therefore, we solve the system of equations simultaneously:\n1) 3x+2y=26\displaystyle 3x + 2y = 26\n2) 6x+y=31impliesy=316x\displaystyle 6x + y = 31 \\implies y = 31 - 6x\n\nSubstitute the expression for y\displaystyle y from equation (2) into equation (1):\n3x+2(316x)=263x + 2(31 - 6x) = 26\n3x+6212x=263x + 62 - 12x = 26\n9x=36impliesx=4-9x = -36 \\implies x = 4\n\nSubstitute x=4\displaystyle x = 4 back into equation (2) to find y\displaystyle y:\ny=316(4)=3124=7y = 31 - 6(4) = 31 - 24 = 7\n\nThus, the mean values are barx=4\displaystyle \\bar{x} = 4 and bary=7\displaystyle \\bar{y} = 7, which corresponds to Option A. (Note: The source file indicating Option B is a typo).\n\nHence, **Option A** is the correct answer.

About This Chapter: Correlation and Regression

Paper

Paper 3: Quantitative Aptitude

Weightage

4-6 Marks

Key Topics

Correlation Coefficient, Regression Equations

This chapter covers Correlation Coefficient, Regression Equations and is part of Paper 3: Quantitative Aptitude in the CA Foundation exam.

View Official ICAI Syllabus

Exam Strategy Tip

This topic carries 4-6 Marks weightage. Focus on understanding core concepts rather than memorizing.

Key Concepts to Understand

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