Question

a college professor inputs test scores for the first two tests of the semester to determine the correlation. the scatterplot for the test scores is shown, along with the line of best fit. choose the best estimate for ( r ), the correlation coefficient.
a (-0.70)
b (-0.30)
c (0.30)
d (0.70)
e (1.0)

Explanation:

Step1: Analyze the scatterplot trend

The line of best fit has a positive slope (as x increases, y generally increases), so the correlation coefficient \( r \) should be positive (eliminating options A and B).

Step2: Assess the strength of correlation

The points are somewhat close to the line of best fit but not extremely close (not \( r = 1.0 \)). A value of \( 0.70 \) indicates a strong positive correlation, while \( 0.30 \) is a weak positive correlation. The scatter of points suggests a stronger positive relationship than \( 0.30 \), so \( r \approx 0.70 \) is more appropriate.

Answer:

D. 0.70