Question

correlation coefficient
which value is the best estimate of the correlation coefficient for the line of best fit for the data?
a ( r = - 0.50 ) b ( r = - 0.10 ) c ( r = 0.40 ) d ( r = 0.95 )

Explanation:

Step1: Analyze the direction of the correlation

The scatter - plot shows that as the number of practice tests (x - axis) increases, the final exam score (y - axis) also increases. So, it is a positive correlation. Options A ($r=-0.50$) and B ($r = - 0.10$) are negative correlations and can be eliminated.

Step2: Analyze the strength of the positive correlation

The data points in the scatter - plot are very close to the line of best fit. A correlation coefficient of $r = 0.40$ (Option C) indicates a weak positive correlation, while a correlation coefficient of $r=0.95$ (Option D) indicates a strong positive correlation. Since the points are close to the line, it is a strong positive correlation.

Answer:

D. \(r = 0.95\)