Question

Zhenghan notices a strong correlation between whether a person is a freshman, sophomore, junior, or senior in college and the number of credit hours that he or she has registered for. As their years in college increase, students tend to register for fewer credit hours. Based on this information, the correlation coefficient between years in college and number of credit hours is closest to _______.

Answer 1

Answer: d) - 0.7

Options:

a) + 0.2.

b) - 0.2.

c) + 0.7.

d) - 0.7.

Explanation: The correlation coefficient is used in statistics to measure the how two variables/events affect each other. The value is always between -1 and +1. A value of -1 or +1 indicates that there is a perfect correlation between the two variables, that is, one is caused by the other. Negative values indicate that as one variable increases the other decreases. On the other hand, positive values mean that as one variable increases the other also increases.

The relationship described here is inverse, that is, as students' years in college increase, they register for fewer credit hours, so this is a negative value. Because the question says the correlation is strong, -7 is more likely than -2. So -7 is the correct answer.