I will really appreciated for the explanation of the answers! 1. John’s parents
ID: 2914713 • Letter: I
Question
I will really appreciated for the explanation of the answers!1. John’s parents recorded his height at various ages between36 and 66 months.
They decide to use the regression line of John’s height onage based on the data to
predict his height at age 21 years (252 months). What conclusioncan we draw?
Age (months) 36 48 54 60 66
Height (inches) 34 38 41 43 45
A. John’s height, in inches, should be about half his age, inmonths
B. The parents will get a fairly accurate estimate of his height atage 21 years.
C. Such a prediction could be misleading, because it involvesextrapolation
D. All of the above.
2. The correlation coefficient between two variables X and Y is r =0.121. What
conclusion can we draw?
A. Because the correlation is so low, the relationship between Xand Y is not very
strong, thus there is no use in studying this relationship.
B. Because the correlation is so low, we only know that the linearrelationship
between X and Y is not very strong, but there may a differentrelationship
between the two variables. We need to first look at ascatterplot.
C. The correlation between X and Y is low, but that does notmatter. A regression
linear y = ax + b is still the best to summarize the relationshipbetween X and Y.
D. None of the above
Explanation / Answer
1. C. Such a prediction could be misleading, because itinvolves extrapolation 2. C. The correlation between X and Y is low, but that doesnot matter. A regressionlinear y = ax + b is still the best to summarize the relationshipbetween X and Y.