Question

Hello,

I need help understanding these problems. I already have the answers for them!

About 1.65 million high-school students took the SATs in 2005. One education researcher (A) used the regression line for predicting Math SAT score from the Critical Reading score. Another researcher (B) believes that verbal ability and mathematical ability have not much of a relationship, and so prefers to use the average Math SAT score as the prediction. It is known that the correlation between the Math SAT score and Critical Reading score is positive. 9. Which researcher will have the smaller RMS error from their method? (a) Researcher A (b) Researcher B 10. How would the correlation change, if we used the Critical Reading score as the response variable, and the Math SAT score as the explanatory (predictor) variable instead? (a) The correlation will increase. (b) The correlation will decrease. (c) The correlation will stay about the same. (d) Not enough information to say what will happen. 11. If it turns out that the RMS errors from both methods are about the same, what does this say about the correlation? (a) The Math SAT and Critical Reading scores are highly positively correlated. (b) The Math SAT and Critical Reading scores are highly negatively correlated (c) The correlation of the Math SAT and Critical Reading scores is close to zero. (d) Not enough information to say anything about the correlation

I don't really understand #9. So researcher A is using the regression line to predict Math SAT from Critical reading score. Researcher B is using Average Math SAT score to predict Critical reading score? How would you calculate RMS error for researcher A and B? I need an explanation please!

10. For this question when you switch critical reading and Math SAT, the correlation will stay about the same.

11. How would you know that if the RMS errors for both are about the same, that the correlation is close to 0? If r=0, then that means that the two variables aren't very closely related right?

Answer 1

SCer