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Questions › JNU › JNU SSS 2017 › Q3
1 mark, −0.25Statistics › Joint distributions, covariance and correlation › The correlation coefficientEasyabout 1 min

JNU SSS 2017 Question 3: Joint distributions, covariance and correlation

XXX is a random variable with mean equal to 1 and variance equal to 9. Let Y=3×X+6Y = 3 \times X + 6Y=3×X+6 and W=−3×X+6W = -3 \times X + 6W=−3×X+6. Which one of the following statements is true?

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X is a random variable with mean equal to 1 and variance equal to 9. Let Y = 3 × X + 6 and W = -3 × X + 6. Which one of the following statements is true? (A) The covariance of W and Y cannot be calculated from the given information. (B) The covariance of W and Y is equal to -9. (C) The correlation coefficient of W and Y is equal to -1. (D) The correlation coefficient of W and Y is equal to 1.

Also written as: X is a random variable with mean equal to 1 and variance equal to 9. Let Y = 3 * X + 6 and W = -3 * X + 6. Which one of the following statements is true?

Joint distributions, covariance and correlation has come up 61 times in 7 exams since 2005.

What this question tests

This question is on The correlation coefficient, part of Joint distributions, covariance and correlation in Statistics.

The standardised measure of linear association and what it can and cannot show.

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