Study Flashcards
A requirement of public health laws established by city or county boards is that they be
approved by referendum
What is a confounding variable
A counfounding variable is associated with exposure; it can strengthen or weaken an association
can adversely affect the relation between the independent variable and dependent variable. This may cause the researcher to analyze the results incorrectly. The results may show a false correlation between the dependent and independent variables, leading to an incorrect rejection of the null hypothesis.
The number of independent events needed for selecting the appropriate probability model is specified by the
of degrees of freedom
Health Impact Assessment
A combination of procedures, methods, and tools by which a policy, program, or project may be judged as to its potential effects on the health of a population, and the distribution of those effect within the population
highest exposure level at which there is no biologically significant increase in the frequency or severity of adverse effect between the exposed population and the control
no observed adverse effect level
Researchers would like to investigate the natural history of a very rare childhood cancer. Which study design is the most appropriate for this study?
Case-control studies are the most efficient designs for the study of rare diseases. This type of study can compare exposures between those with the disease and those that do not have the disease.
The number of deaths among infants aged 0 to 365 days during the year divided by the number of live births during the year defines
infant mortality rates
Which of the following factors is thought so have the smallest impact on the health of the U.S. population?
medical care
Community health workers can be most useful in which of the following health promotion activities:
Lay health workers can be more credible delivers of health education interventions because they are trusted to understand the norms, values, customs and traditions of the target community.
Robust
statistical procedure that is not sensitive to departures from the conditions on which it is based.
The mission of which federal entity is to ensure safe and healthful working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education, and assistance
OSHA
Which type of dose is most relevant for determining the toxicity of an agent?
Target organ dose
A chi-square goodness-of-fit test is always conducted as
upper tailed test
P-value
probability that a test statistic would be as extreme as, or more extreme than, observed if they null hypothesis were true. P-value is a statement of the probability that the difference observed by chance if the groups were really alike, i.e., under the null hypothesis.
Given a point estimator, its standard deviation is called?
The standard error represents the estimated standard deviation obtained from a set of sample means from repeated samples of size n form a population with underlying variance α2
Mortality Rate (i.e. fatality rate)
MR = d/N(T) where: d = # of deaths N = total population at mid-point of time period T = follow-up time (usually 1 year)
Case Fatality Rate
not a rate, this is a proportion!!) Proportion of deaths from a specific illness Case Fatality Rate = a/N where: a = # of deaths from an illness N = # of people with that illness
Crude Mortality Rate
all deaths, total population, in a time period
cohort studies
groups, defined on the basis of some characteristics (often exposure and non-exposure) are typically followed to see whether an outcome of interest occurs
Comparison of Interest: Compare the proportion of persons with the disease in the exposed group to the proportion with the disease in the unexposed group
Case-control Studies
compare various characteristics (past exposure) for cases to those of controls (i.e. goes from present disease status to past exposure status)
Comparison of Interest: Compare the proportion with the exposure in cases to the proportion with exposure in control group
Cross-sectional Studies
prevalence studies (i.e. snapshot)
All measurements of exposure and outcome are made simultaneously
Disease proportions are determined and compared among those with or without the exposure or at a varying level of the exposure
Examine association – determination of associations with outcomes; generates hypotheses that are the basis for further studies
Most appropriate for studying the associations between chronic diseases and chronic exposure
Correlational/Ecological Studies
The unit of observation is the population or community
Disease rates and exposures are measured in each of a series of populations
Disease and exposure information may be abstracted from published statistics and therefore does not require expensive or time consuming data collection
Measures that represent characteristics of the entire population are used to describe disease in relation to some factor of interest
Relative Risk
an estimate of the magnitude of an association between exposure and disease; indicates the likelihood of developing the disease for the exposed group relative to those who are not exposed
For RR > 2.0: RR is the # of times increased risk, e.g. RR=3.0 means 3 times increased risk of outcome given exposure
For RR
Null hypothesis
the risk of the outcome in exposed persons is equal to the risk of the outcome in the unexposed persons
H0 =
odds ratio
Odds Ratio = odds of exposure in case/odds exposure in controls
OR = 1: Exposure is not associated with the disease
OR > 1: Exposure is positively associated with the disease
OR
how is odds ratio different than risk ratio
OR: The odds of exposure among the diseased is x times higher/lower than the odds of exposure among non-diseased
RR: The risk of disease among the exposed is x times higher/lower than the risk of disease among unexposed
sufficient cause vs necessary cause
Sufficient Cause – precedes the disease, can cause disease by itself
If the cause is present, the disease always occurs
Necessary Cause – precedes the disease, must be present for disease to occur
If the cause is absent, the disease cannot occur
passive surveillance
gathers disease data from all potential reporting health care workers
active surveillance
provides stimulus to health care workers in the form of individual feedback or other incentives.
sentinel surveillance
selects, either randomly or intentionally, a small group of health workers from whom to gather data
linear regression
modeling the relationship between a scalar dependent variable y and one or more explanatory variables (or independent variables) denoted X.
The t-distribution approaches what distribution as its degrees of freedom increases?
The overall shape of the density function of the t-distribution resembles the bell shape of the normal distribution with mean 0 and variance 1, except that is a bit lower and wider. As the number of the degrees of freedom increases, the t-distribution approaches the normal with mean 0 and variance 1.
health risk assessment equation
risk=hazardXexposure
