Epidemiology Exam 1 (updated)

To study the distribution and determinants of health and diseases, morbidity, injuries, disability, and mortality in populations. Epidemiological studies are applied to the control of health problems in populations. The primary focus is the general population, sometimes called "population medicine." Purpose: Health promotion, alleviation of adverse health outcomes, prevention of disease, control of health problems (e.g., infectious, communicable and chronic disease).

Histogram: Represents the frequency distribution of continuous variables. Presents numerical data. Drawn with no gap between the bars. Bar chart: Shows the frequency of cases for categories with discrete variables (e.g., qualitative, discrete, Yes/No variable). Presents categorical data.

Epidemic: A widespread occurrence of an infectious disease or other specific health-related behavior in a community at a particular time. Endemic: A disease that exists permanently in a particular region or population. Malaria is a constant worry in parts of Africa. Chickenpox is endemic in the UK, but malaria is not.

Incidence: Refers to the occurrence of a new disease or mortality within a defined period of observation (e.g., a week, month, year, or other time period) in a specified population. Prevalence: The number of existing cases of a disease, health condition or deaths in a population at a specific time.

Behavioral science/health education. Biostatistics. Environmental health. Epidemiology. Health services administration.

To describe the health status of populations To explain the causes of disease To predict the occurrence of disease To control the occurrence of disease

Analytical: Examines casual (etiologic) hypothesis regarding the association between exposures and health conditions. Searches for causes and effects, or the why and how. Descriptive: Aims to characterize the amount and distribution of health and diseases within a population.

Used to project population changes. Formula: (# of deaths in a given year)/(reference population at midpoint of the year) x 100,000

He was an English anesthesiologist who innovated several of the key epidemiological methods that are used today. He believed that cholera was transmitted by contaminated water and was able to demonstrate this association. Contributions: Powers of observation and written expression, application of epidemiological methods (used mapping and data tables to describe infectious disease outbreaks), recommended a public health measure to prevent disease.

Median: 110

Increase

Decrease in incidence, shorter duration of the case, in-migration of healthy people, improved cure rate of the disease

A sampling technique in which the researcher selects samples based on the subjective judgment of the researcher rather than random selection. Creation of non-representative samples.

The researcher divides the population into separate groups, called strata. Then, a probability sample (often a simple random sample ) is drawn from each group. Stratified sampling has several advantages over simple random sampling.

A random process selects the samples. Unbiased. The average of the sample estimates over all possible samples is equal to the population parameter.

A type of non-probability sampling method where the sample is taken from a group of people easy to contact or to reach. For example, standing at a mall or a grocery store and asking people to answer questions would be an example of a convenience sample.

Systematic sampling is a probability sampling method where the elements are chosen from a target population by selecting a random starting point and selecting other members after a fixed 'sampling interval'. There's an equal opportunity for every member of a population to be selected. (Ex: in a population of 10,000 people, a statistician selects every 100th person for sampling. The sampling intervals can also be systematic, such as choosing a new sample to draw from every 12 hours.)

A display table that shows how often each item, number or range of numbers occur in a data set.

Shows the frequency of cases for categories of a discrete variable (e.g., qualitative, discrete variable such as Yes/No).

A chart that shows the relationship of a part to a whole. Shows the proportion of cases according to several categories. The size of each piece of the pie is proportional to the frequency of the cases.

Represents the frequency distribution of continuous variables. Presents numerical data. Drawn with no gap between the bars.

(# of persons ill at a point in time)/(total # in the group)

(# new cases in population during specific time period)/(average population at risk) x multiplier (100,000)

(# of new cases over a period of time)/(total population at risk over the same time period)

Another method for demonstrating associations. A type of table that tabulates data according to two dimensions.

Measure of association used with continuous variables. Varies from -1 to 0 to +1. The value of 0 means no association. As (r) approaches either -1 or +1, the association between the two variables becomes stronger. When (r) is negative, the association is inverse.

A graph with points plotted to show a possible relationship between two sets of data.