Identify the following as paired samples or independent samples. In each case, give the appropriate df.

a. Thirteen volunteers weighed themselves before and after a two-day fast.

b. The attitudes toward plagiarism of 21 famous psychologists were compared to those of each one's designated "best student."

c. Eight volunteers each rated their emotionality in a large blue room and then in a small yellow one.

d. A psychologist gave a pretest and matched each participant with another participant. Half were given an amphetamine and half were given a placebo. All 40 participants then learned a new task.

e. The first 10 persons who arrived for a church service filled out a questionnaire on attitudes toward religion. The first 10 who were late for the service were spotted and, after the service, they filled out the same questionnaire.