John Snow’s conclusions that contaminated water was associated with cholera was based entirely on... (choose one best answer)

Edward Jenner was able to find a vaccination against smallpox because (choose one best answer):

In present time the three most common causes of death in the U.S. are … (choose one best answer)

Cervical cancer screening (PAP smear) is an example of secondary prevention: (choose one best answer)

Tertiary prevention denotes the early detection of a disease to reduce its severity and complications. (choose one best answer) 

Dengue fever is a disease caused by a virus that spreads to people mostly from the bites of a special type of mosquito, Aedes aegypti (yellow fever mosquito).  Such transmission is an example of (choose one best answer):

A disease that is habitually present in a population/community is defined as … (choose one best answer):

Case-fatality (stated as a percent) is... (choose the one best answer)

In a screening test for a cancer, out of 150 people tested, 20 tested positive but actually did not have disease. These 20 people could be referred to as … (choose one best answer):

Using a test of given sensitivity and specificity, the positive predictive value of the test typically increases as disease prevalence decreases. (choose one best answer)

Sequential testing results in an increased of net specificity and loss in net sensitivity. (choose one best answer)

Power of the study is ... (choose one best answer).

A clinical trial was done of obesity reduction by liposuction versus prescription-only diet   pills (i.e., medical). Following randomization, 23% of the liposuction group changed their mind and asked their doctors for diet pills and 28% of the diet pill group changed their mind and asked for liposuction This is an example of: (choose the one best answer)

The use of a placebo in a randomized clinical trial is a form of... (choose one best answer)

In a cohort study incidence in exposed and unexposed groups can be calculated and compared. (choose one best answer)

Which of the following is not an advantage of a prospective cohort study?

The National Death Registry identifies deaths anywhere in the United States if linking information is known, such as sex, race, date of birth, and social security number. All of these variables were collected by UCLA from students in the class of 1953 at the time they were enrolled. Fifty years later, their UCLA grades were used to compare mortality rates among the upper fourth versus the lower fourth of the graduating class. This study is an example of a... (choose one best answer)

Odds ratio is a good estimate of relative risk (or risk ratio) under rare disease assumption. (choose one best answer)

The most important step in case-control studies is … (choose one best answer)

One of disadvantages of using hospital-based controls is ... (choose one best answer):

Four thousand persons were interviewed by telephone in California between January and June, 2008. In this single-contact study, persons were asked about their height, weight and systolic blood pressure. The researchers combined the height and weight to form the body mass index (i.e., BMI) and found that the BMI was positively associated with systolic hypertension. This study is an example of a... (choose one best answer)

The most important criteria to assess causation is ... (choose one best answer):

In observational studies one of the main biases that may affect the results of a study is confounding.

In a study on the association between consuming greasy food and acne, people without acne may be more likely to forget/misremember their exposure to greasy foods than those with acne. The potential distortion in results this may lead to can be identified as a form of recall bias. (choose one best answer)

Confounding is one of the most important problems to consider and to account for when interpreting an observed association between an exposure and a disease. (choose one best answer)

Undue influence in a research study occurs when an offer of an excessive or inappropriate reward or other gesture is offered to obtain consent and compliance. (choose one best answer)

The primary purpose of an Institutional Review Board (IRB) is to ensure that a research study generates the highest amount of profit possible. (choose one best answer)

Criterion for causation, stating that if a relationship is causal an exposure of interest should precede a disease of interest is called temporality. (choose one best answer):

Criterion for causation, stating that if a relationship is causal, we would be more likely to expect to find it repeatedly in different studies and in different populations is called specificity.