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NDA 2021
Exam
NDA
Year
2021
Subject
Mathematics
Chapter
Statistics

NDA 2021 · Mathematics · Statistics

Two regression lines are given as 3 x-4 y+8=0 and 4 x-3 y-1=0 ....

Two regression lines are given as 3x−4y+8=03 x-4 y+8=0 and 4x−3y−1=04 x-3 y-1=0. Consider the following statements : 1. The coefficient of correlations rr is 34\frac{3}{4}. 2. The means of xx and yy are 3 and 4 respectively. Which of the above statements is/are correct?

Options

  1. A1 only
  2. B2 only
  3. CBoth 1 and 2
  4. DNeither 1 nor 2

Correct answer

A. 1 only

Step-by-step solution

co-efficient of correlations. ∣r∣=byx⋅bxy=34×34=34⇒r=±34\begin{aligned} & |r|=\sqrt{b y x \cdot b x y}=\sqrt{\frac{3}{4} \times \frac{3}{4}}=\frac{3}{4} \\ & \Rightarrow r= \pm \frac{3}{4} \end{aligned} Since byxandbxyb y x and b x y are positive ∴r=34\therefore r=\frac{3}{4} This means xandyx and y have positive relationship (increasing).
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