Question

Andy is trying to determine the correlation between the number of math homework assignments he completes and his test score. Which is the BEST estimate for the correlation coefficient of the data? A) r = 1.5 B) r = 0.5 C) r = 0.96 D) r = −0.90

Answer 1

Answer option C:
The model is close to being linear. Therefore, there is a strong positive correlation.

Answer 2

Option C

Explanation:

It is really obvious that whenever the number of homework assignments he completes increases, his knowledge in the subject increases. This will increase automatically his test score in Maths.

Thus we can expect a perfect linear association between number of assignments done and his test score.

The correlation coefficient which is a measure of linear association between two variables always lies between -1 and +1.

Hence Option a cannot be correct since the value is greater than 1.

b) r=0.5 gives a positive but not very strong association. This is wrong as there is a strong association between the two variables

c) r=0.96 seems to be a correct answer as the positive and near to 1 r value confirms the linear strong positive association between the two variables.

D) r =-0.90 is wrong since there cannot be a negative association.

So only option right is option C