# Interpreting Data on Risk Factors

## Types of Data

• Epidemiologists use quantitative data, which are numerical values, and qualitative data, which are descriptive or categorical values.

• Primary data is collected directly from the source, such as from a survey or experiment, while secondary data is collected from existing sources.

• The two main types of study designs are observational studies and experimental studies. In observational studies, researchers observe and measure variables without influencing them aside from what is natural. In experimental studies, researchers manipulate and control one or more variables to determine their effects.

## Using Graphs and Charts

• Risk factor data is often displayed in the form of graphs and charts, such as bar graphs, pie charts, scatter plots, or histograms. Understanding these graphical representations is key in interpreting data.

• Correlation in a scatter plot suggests a relationship between two variables, but does not prove causation.

## Understanding Statistical Terms

• Population refers to the entire group that is being studied, while a sample is a subset of the population.

• Statistical significance is a measure of whether the results are likely to be due to a true difference rather than just chance variation.

• Correlation coefficients range from -1 to 1 and indicate the strength and direction of a relationship between two variables; a coefficient near 0 suggests no correlation, a positive coefficient suggests a direct positive correlation, and a negative coefficient suggests an inverse relationship.

• Confounding variables are outside influences that can disrupt the relationship and affect the accuracy of a study.

## Evaluating and Comparing Data

• When evaluating the reliability of data, consider factors such as sample size, potential biases, and whether the study was peer-reviewed.

• When comparing data from different studies, it is important to consider the study designs used. Some study designs provide stronger evidence than others.

• Always consider whether the data supports the conclusions of the researchers. Sometimes, researchers might overstate the significance of their findings.

## Ethical Considerations

• Ethical considerations in epidemiological studies include obtaining informed consent from participants, ensuring confidentiality of data, and avoiding harm to participants.

• The use of animals in biomedical research has ethical implications. The principles of Replacement, Reduction and Refinement (the 3Rs) are applied to ensure ethical use of animals in research.