The environmental and reproductive health departments at UCSF studies the interaction of pregnancies outcomes and chemical exposures. One study that was just funded looks at preterm birth weight and exposure to perfluorooctanoic acid (PFAS), a common chemical added to non-stick cookware. The study has 1,000 participants, 495 that had a low preterm birth weight (under 5 lbs) and 505 that had high preterm birth weights (>5 lbs). In terms of exposure, 950 of them were exposed to PFAS daily during their pregnancy and 50 were not.

What are the independent and dependent variables in this sample?

a. dependent = pregnancy, independent = PFAS exposure

b. dependent = preterm birth weight, independent = PFAS exposure

c. dependent = PFAS exposure, independent = preterm birth weight

d. dependent = pregnancy, independent = preterm birth weight

e. dependent = PFAS exposure, independent = pregnancy

A study was conducted to assess the use of white noise on test scores. 9 students were randomly selected. In the first part of the study, the students were given 45 minutes to complete a high school level math test with 30 questions. This exam was administered in silence. For the second part of the study, the students were given the same exact exam and time limit, but this time they were given headphones to listen to white noise as they completed the exam. Using a 0.05 significance level, test the claim that the test scores for no noise is different than for white noise. The scores for the students' exams are as follows: