Applied Epidemiology and Biostatistics Midterm 522 Rush Exam 2025

The study of the distribution and determinants of heath-related states or events in specified populations, and the application of this knowledge to the control of health problems - -What is Epidemiology Distribution - -Refers to person, place, and time Determinants - -Physical, biological, social, cultural, economic and behavioral factors that influence health Health-Related States or Events - -Includes wellness, illness, disease, injury, impairments, and disability Specified Populations - -The characteristics of who is healthy, who is at risk for the disease, and who acquires the disease Control of Health Problems - -The goal of epidemiology is to identify factors associated with the development of disease as well as factors that prevent illness Epidemiology focuses on _______________ - -*Populations* & *Population Health* Not focused on providing direct care to individuals 6 Core Epidemiological Functions - -Surveillance Field Investigations Analytical Studies Evaluation *Linkages* Policy Epidemiology is a ____________ science - -Quantitative Study - -Refers to systematic surveillance, observation, experimentation... use of a scientific approach Two Major Branches of Epidemiology - -Descriptive Epidemiology: *distribution, frequency, and pattern* of health-related states and events (the who, where, when/person, place, time) Analytic Epidemiology: *determinants* of health-related states and events (the why/causes) EPIDEMIOLOGY EPIDEMIOLOGY Mission of CDC - -Protect the health of the nation Variable - -Any characteristic that can vary; the thing being measured or observed T/F: An operational definition defines how a variable will be measured, and includes the equipment and procedures that are used in the measurement. - -True The conceptual definition of a variable: a. Explains what the variable means. b. Specifies how a variable should be measured. c. Describes the standards for measuring a variable. d. Specifies the precision of the measurements. - -a. Explains what the variable means Conceptual Definitions - -*Defines the variable*; dictionary definition Operational Definitions - -Specifies how variable is measured; describes *operations used to obtain measurement* The dependent variable is: a. The intervention being studied. b. The outcome variable. c. The variable manipulated by the researcher. d. A characteristic of the person being studied. - -b. The outcome variable Independent Variable - -Manipulated in a study to see if it affects the outcome(s) being studied Intervention/treatment Usually only 1 Effects/causes the outcome of interest T/F: A study can have more than one dependent (outcome) variable. - -True Dependent Variable - -*Outcome*/response variable(s) Can be more than 1 Caused by independent variable T/F: The reliability of a weight measurement obtained with an electronic scale refers to the accuracy of the measurement. - -False EPIDEMIOLOGY EPIDEMIOLOGY EPIDEMIOLOGY Testing a new piece of equipment to ensure that the equipment consistently provides that same measurement when the same variable is measured multiple times is an example of a. Validity b. Reliability c. Accuracy d. All of the above - -b. Reliability Reliability - -Refers to the *repeatability or reproducibility* of the measurements Validity - -Is about the *accuracy* of data Addresses whether the measurement truly measures the variable of interest Two types of Categorical Data - -*Nominal* (named categories) and *Ordinal* (ranked categories) Nominal Data - -Data classified into categories with names ex. race, gender, ethnicity, relationship status, disease status, consent, y/n, blood type Ordinal Data - -Categories that have an order/rank to them ex. grades A,B,C,D,F; pain level, education level, cancer stages A variable was recoded as disease present, disease not present, or unknown. When performing the descriptive statistics, which of the following should be used? SELECT ALL THAT APPLY a. Epidemiological range b. Percentages c. Median d. Frequencies e. Mode - -b. Percentages d. Frequencies T/F: The frequency and relative frequency presented as a percentage should be reported when describing nominal level data. - -True Data Analysis for Categorical Data - -Description of Categorical Data (nominal/ordinal): Frequencies (counts) (n or f) Percentages (%) Relative Frequency (%) - -Proportion of the total number of observations in each category EPIDEMIOLOGY EPIDEMIOLOGY Satisfaction with care is rated on a scale from 1 (extremely dissatisfied) to 6 (extremely statisfied). The scores would best be displayed using a a. Histogram b. Pie Chart c. Bar Chart d. Box-and-whisker plot - -a. Histogram (Ordinal) When analyzing the variable gender, which was measured in 5 categories (male, female, transgender male, transgender female, other), the data should be displayed using a a. Bar Chart b. Histogram c. Line Chart - -a. Bar Chart Graphic Display for Nominal Data - -Bar Charts Graphic Display for Ordinal Data - -Histogram Two types of Continuous Data - -*Interval* (no meaningful zero) & *Ratio* (meaningful zero) Interval Data - -Interval between each number is equal, no absolute zero ex. temperature F and C, standardized tests Ratio Data - -Interval between each number is equal and there is a meaningful zero ex. age, height, weight, BMI, HR, BP Description of Continuous Data - -Measures of Central Location Measures of Spread Graphic Display Test of Normality Measures of Central Location - -Mean, median, mode (routinely performed in initial assessment of all continuous variables) Geometric mean, midrange Determines measure of spread that should be reported The decision to use the median or mean is