1. Suppose a Guilford County High School Gym teacher wants to study the frequency of knee injuries in students involved in high-school sports. As a part of this study, he also wishes to study if there is an association between student players' sex and if they have experienced a knee injury. Here the two variables being studied are:

Variable 1: Sex of students involved in sports (Responses: Male/Female).

Variable 2: Whether or not a student involved in sports has experienced a knee injury (Responses: Yes/No).

What would be the best way to study the association between these two variables?

A. Calculate the correlation between the values of the two categorical variables.

B. Draw a scatterplot of the responses for whether the respondents have experienced a knee injury and their sex.

C. Make a two-way table of the responses forsex and the knee injury experience status.

D. All of the answers are correct.

2. Vivek notices that students in his class with larger shoe sizes tend to have higher grade point averages (GPA). He created a scatter plot and saw a linear trend and found r = .89. Based on this observation, He concluded that if he had a bigger shoe size he would make a very high GPA. What is wrong with this interpretation?

A. Vivek is using the wrong type of plot, therefore the results are invalid.

B. Since r = .89 you know the slope will be negative so having a bigger shoe size a long time will give you a lower GPA.

C. Vivek is assuming that correlation implies causation i.e. just because there is an association between a higher GPA and a bigger shoe size, it doesn't mean every student who has a bigger shoe size will have a high GPA.

D. Nothing is wrong with his interpretation