Statistical Problems on Epidemiology

Statistical Problems on Epidemiology
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Answer 1: (F)
Reason: Internal validity refers to the success of an experiment. It also checks if there is more
than one possible variable acting at the same time.
Answer 2: (T)
Reason: Research bias, also called experimenter bias, is a process where the scientists
performing the research influence the results, in order to portray a certain outcome. Some bias in
research arises from experimental error, and failure to take into accounts all of the
possible variables. Other bias arises when researchers select subjects that are more likely to
generate the desired results, a reversal of the normal processes governing science.
Answer 3: (T)
As the confidence level increases, the width of the confidence interval also increases. This
increases the precision of the experiment. However, the accuracy decreases.
Answer 4: (T)
In the case control, design initiates with part of the results, that are cases and bases or controls or
referents (coincidental or not), and try to study what was the exposure.
Answer 5: (T)
The result rate is usually lower than the prevalence of exposure; Cohort studies generally require
larger samples to have the same potency as a case-control study.

Answer 6: (T)
The design of the case-control study is frequently used in the learning of rare diseases or as a
prelude study where little is known about the alliance between the risk factor and the disease of
interest.
Answer 7: (T)
Cross-sectional study investigates the information from a population or a representative subset,
at a specific point in time.
Answer 8: (T)
In the AB / BA crossover study, the sample group is divided into two subgroups. The first group
receives first treatment "A" and then treatment "B". The second group receives treatment "B"
first and then treatment "A". Here each patient serves as his own control
Answer 9: (T)
As each patient fulfills requirement of his or her own control in a cross-over study, variation in
response between patients is eliminated when comparing treatments.
Answer 10: (F)
Cross-design would not be effective in comparison with treatments, because the effects of
training in the cross design result in a substantial loss of efficiency in estimating the relative
effect of treatment (Dutra & Glantz, 2014).