Tail-feather length in birds is sometimes a sexually dimorphic trait. That is, the trait differs substantially for males and for females. Researchers studied the relationship between weight (x) and tail-feather length (y) in a sample of five wild male long-tailed finches. Here are the data:
What is the approximate value of the correlation coefficient between weight and tail feather length?
$$\begin{array} { c c }
\text { weight } ( \mathrm { g } ) & \text { tail length } ( \mathrm { mm } ) \
20.8 & 82.5 \
19.1 & 82.5 \
15.9 & 67.0 \
16.7 & 70.5 \
15.7 & 73.5
\end{array}$$

Question

Tail-feather length in birds is sometimes a sexually dimorphic trait. That is, the trait differs substantially for males and for females. Researchers studied the relationship between weight (x) and tail-feather length (y) in a sample of five wild male long-tailed finches. Here are the data:
What is the approximate value of the correlation coefficient between weight and tail feather length?
 $$\begin{array} { c c } 
\text { weight } ( \mathrm { g } ) & \text { tail length } ( \mathrm { mm } ) \
20.8 & 82.5 \
19.1 & 82.5 \
15.9 & 67.0 \
16.7 & 70.5 \
15.7 & 73.5
\end{array}$$

Quizplus · Accepted Answer

To find the correlation coefficient, we use a calculator or statistical software. Using the given data, the correlation coefficient (r) is approximately 0.888, which indicates a strong positive linear relationship between weight and tail feather length in male long-tailed finches.

Tail-Feather Length in Birds Is Sometimes a Sexually Dimorphic Trait