Questions: Find the value of the linear correlation coefficient (r). The paired data below consist of the temperatures (in degrees Fahrenheit) on randomly chosen days and the amount a certain kind of plant grew (in millimeters).
Temperature 62 76 50 51 71 46 51 44 79
Growth 36 39 50 13 33 33 17 6 16
0
0.256
-0.210
0.196
Transcript text: Find the value of the linear correlation coefficient $r$. The paired data below consist of the temperatures (in degrees Fahrenheit) on randomly chosen days and the amount a certain kind of plant grew (in millimeters).
\begin{tabular}{l|lllllllll}
Temperature & 62 & 76 & 50 & 51 & 71 & 46 & 51 & 44 & 79 \\
\hline Growth & 36 & 39 & 50 & 13 & 33 & 33 & 17 & 6 & 16
\end{tabular}
0
0.256
$-0.210$
0.196
Solution
Solution Steps
Step 1: Calculate Covariance
The covariance between the temperature \( X \) and the growth \( Y \) is calculated as follows:
\[
\text{Cov}(X,Y) = 38.125
\]
Step 2: Calculate Standard Deviations
The standard deviation of the temperature \( X \) is given by:
\[
\sigma_X = 13.439
\]
The standard deviation of the growth \( Y \) is given by:
\[
\sigma_Y = 14.509
\]
Step 3: Calculate Correlation Coefficient
The correlation coefficient \( r \) is calculated using the formula:
\[
r = \frac{\text{Cov}(X,Y)}{\sigma_X \sigma_Y}
\]
Substituting the values:
\[
r = \frac{38.125}{13.439 \times 14.509} \approx 0.196
\]