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PRMIA Exam 8002 Topic 3 Question 73 Discussion

Actual exam question for PRMIA's 8002 exam

Question #: 73
Topic #: 3

[All 8002 Questions]

You are to perform a simple linear regression using the dependent variable Y and the independent variable X (Y = a + bX). Suppose that cov(X,Y)=10, var(X)= 5, and that the mean of X is 1 and the mean of Y is 2. What are the values for the regression parameters a and b?

Ab=0.5, a=2.5

Bb=0.5, a=1.5

Cb=2, a=4

Db=2, a=0

Show Suggested Answer

Suggested Answer: D

by Marguerita at Feb 08, 2024, 04:44 PM

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Ines

7 months ago

Exactly, a = 2 - 2*1 = 0 and b = 2, so the answer is D) b=2, a=0

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Dalene

7 months ago

To find a, we can use the formula a = mean(Y) - b*mean(X)

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Gilma

8 months ago

So, b = 10/5 = 2, but what about a?

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Casie

8 months ago

I believe the formula for regression coefficient b is cov(X,Y)/var(X)

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Ines

8 months ago

I think we can calculate the values using the provided information

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Teddy

8 months ago

I'm leaning towards option C) b=2, a=4 because it seems to make more sense mathematically.

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Thurman

8 months ago

I disagree, I believe the correct answer is B) b=0.5, a=1.5 based on the means of X and Y given in the question.

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Ronna

8 months ago

I think the answer is A) b=0.5, a=2.5 because of the given covariance and variance values.

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