Question

question 9 of 25
which correlation coefficient indicates a strong positive correlation?

a. ( r = -0.1 )

b. ( r = -0.09 )

c. ( r = +0.9 )

d. ( r = +0.5 )

Explanation:

Step1: Recall correlation coefficient rules

The correlation coefficient \( r \) ranges from \(-1\) to \( +1 \). Positive \( r \) means positive correlation, negative \( r \) means negative correlation. The closer \( |r| \) is to \( 1 \), the stronger the correlation.

Step2: Analyze each option

• Option A: \( r = -0.1 \) is negative (negative correlation) and weak (\( |r| = 0.1 \) close to 0).
• Option B: \( r = -0.09 \) is negative (negative correlation) and very weak (\( |r| = 0.09 \) close to 0).
• Option C: \( r = +0.9 \) is positive, and \( |r| = 0.9 \) is close to \( 1 \), so strong positive correlation.
• Option D: \( r = +0.5 \) is positive but \( |r| = 0.5 \) is moderate (not as strong as 0.9).

Answer:

C. \( r = +0.9 \)