Question

ST201 Online Exam Scores for Summer 2017 Term 70 75 80 95 85 90 Midterm Percentage Pr(> | t |) Estimate StdError T value (Intercept) 19.31 -1.23 -23.8 0.224 <e.0001 5.4 0.23 1.2 Midterm Part 2. (8 points) Describing the relationship between the two variable (2 points) Which variable is the explanatory variable and which is the response? b. (3 points) Describe in context the relationship from the scatterplot. Include strength, direction, form and outliers (if any). c. (3 points) One of the following is the exact correlation coefficient a. 0.13 0.98 0.62 -0.65 WE T 00 0L 09 06 Final Percentage

Answer 1

a) The explanatory variable is Midterm Percentage. The response variable is Final percentage

b) From the scatterplot, we can say that the relationship between the variables is positive. As the midterm percentage increases, the final percentage increases too. The strength of the relationship is moderately strong and there is a linear association. There seems to be a few potential outliers.

c) -0.65 can't be the correlation coefficient (r) as the relationship is not negative
0.98 can't be true as well as the relationship is not too strong (nearly perfect)
0.13 is wrong as the relationship is not too weak. The relationship seems to be moderately strong.

Hence, the correct correlation coefficient is 0.62