Epidemiology Quiz: Knowledge Trivia! Test

A cohort study is a type of longitudinal or prospective study where a group of individuals with a common characteristic or exposure are followed over a period of time to observe the development of specific outcomes. This type of study design allows researchers to investigate the cause-and-effect relationship between the exposure and the outcome. Therefore, the correct answer for this question is cohort study.

Randomization is a way to deal with confounding in a study. It involves randomly assigning participants to different groups, such as an exposed group and an unexposed group. This helps to ensure that any potential confounding factors are distributed equally among the groups, reducing the likelihood of bias. By randomly assigning participants, the study design can help control for potential alternative explanations and increase the validity of the results.

The crude mortality rate for Cedar Rivers in 2008 was 10 per 1,000. This is calculated by dividing the number of deaths (1,000) by the population size (100,000) and then multiplying by 1,000 to express it per 1,000 population. The information about tuberculosis deaths in 2007 and 2008 is not relevant to calculating the crude mortality rate.

The specificity of the doctors' clinical judgment is calculated by dividing the number of true negatives (patients with negative cultures correctly diagnosed as not having strep throat) by the total number of patients with negative cultures. In this case, there were 112 patients with negative cultures and the doctors correctly diagnosed 77 of them as not having strep throat. Therefore, the specificity is 77/112.

The sensitivity of clinical diagnosis refers to the proportion of true positive cases that are correctly identified as positive by the clinical diagnosis. In this case, the numerator represents the number of clinically diagnosed gastric and peptic ulcers that were confirmed by autopsy (1,500), and the denominator represents the total number of autopsy-confirmed cases (4,000). Therefore, the correct answer is 1,500/4,000.

The P-value of 0.4 indicates that there is a 40% chance of observing the results of the study if the null hypothesis (no difference between the new drug and usual care) is true. This means that the results are not statistically significant, and therefore, it is not possible to conclude that one treatment is better than the other based on this information alone.

The measure of association for each food item is calculated based on the number of people who ate the food and developed gastroenteritis. The largest measure of association indicates the highest association between consuming the food item and developing gastroenteritis. Therefore, the explanation for the correct answer, which is Ice Cream, is that it had the highest number of people who ate it and developed gastroenteritis compared to the other food items.

The odds ratio is not an estimate of relative risk, as stated in the first option. The odds ratio is a measure of association between exposure and outcome in a case-control study, and it can be calculated without data on rates. However, it is not the ratio of incidence in exposed divided by incidence in nonexposed. The odds ratio compares the odds of exposure in cases to the odds of exposure in controls. It tends to be biased towards 1 at high rates of disease because as the disease becomes more common, the odds ratio becomes a less accurate estimate of the relative risk.

The study in Question 3 found that the predictive value of the doctors' clinical judgment for streptococcal sore throat was 27/62. This means that out of the total number of cases evaluated by the doctors, 27 were correctly diagnosed as streptococcal sore throat while 35 were incorrectly diagnosed. Therefore, the doctors' clinical judgment had a success rate of 27 out of 62 cases.

The given question is asking about the areas of relative strength and relative weakness of the new test for prostate cancer. The information provided states that the test yields the same results for every individual repeatedly, indicating its reliability. However, there is a low correlation between this new test and existing tests with proven track records, suggesting a weakness in terms of validity. Therefore, the correct answer is reliability and validity.

A vehicle is a mode of transport that carries an infectious agent through the environment to a susceptible host. This can include objects, such as contaminated food or water, that act as intermediaries in transmitting the infectious agent. Unlike carriers, which are individuals who harbor and spread the infectious agent without showing symptoms, a vehicle does not necessarily involve a living organism. A reservoir refers to the natural habitat where the infectious agent lives and multiplies, while a vector is an organism, such as a mosquito, that transmits the infectious agent.

The predictive value of a positive test is 67% because it is calculated by dividing the number of true positive results (100) by the sum of true positive and false positive results (100 + 50). This gives us a fraction of 100/150, which simplifies to 2/3 or 0.67 when expressed as a decimal. Multiplying this by 100 gives us the percentage of 67%.

The term "clinical trial" refers to a research study conducted on humans to evaluate the safety and effectiveness of a medical intervention, such as a drug. "Full scale Evaluation of Treatment" accurately describes this process, as it involves a comprehensive assessment of the treatment's efficacy and potential side effects in a larger population. The other options, such as "Clinical pharmacology and toxicity" and "Initial Clinical Investigation for Treatment Effect," may be related to aspects of the drug trial but do not encompass the entire process. "Post marketing Surveillance" refers to monitoring the drug's safety and effectiveness after it has been approved and is being used by the general public.