Q78 · CSIR-NET Chemistry, June 2013

Paper: CSIR-NET June 2013 · Subject: Physical Chemistry · Chapter: Data Analysis · Topic: Regression Fitting · Marks: 2 · Difficulty: Medium

For two variables x and y , the following data set is given:

The correct statement for the covariance A and correlation coefficient B of x and y is

(a)$\mathrm{A}=2 / 3, \mathrm{B}=1$

(b)$\mathrm{A}=-2 / 3, \mathrm{B}=1$

(c)$\mathrm{A}=-2 / 3, \mathrm{B}=-1$

(d)$\mathrm{A}=0, \mathrm{B}=0$

Answer

Answer: A ✓ checked by 4AB · confidence high

Explanation

x̄ = 0, ȳ = 2: cov = Σ(x − x̄)(y − ȳ)/n = (1 + 0 + 1)/3 = 2/3; the points lie exactly on y = x + 2, so r = 1.

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