Which of the following statements are true and which are false?
a. In a paired design, each pair of observations always consists of measuring the same individual twice.
b. In a paired design, each pair of observations often consists of measuring the same individual twice.
c. In an independent groups design, each individual in a group is unrelated to all the other individuals in the study.
d. When a paired design is possible, you typically get more informative results because units within a pair tend to be similar to each other.