MIDTERM Flashcards
Define
What is epidemiology?
Lecture 1
the study of the distribution and determinants of health-related states or events among specific populations and the application of the study to the control of health problems
Epidemiology: True or False
Epidemiology is often described as the basic science of public health.
True
Epidemiology
What is distribution?
Lecture 1
frequency + pattern
- in other words: “how many people?” + “where?”
Epidemiology: Distribution
Define frequency
Lecture 1
- the number of health-related events
- how often these events occur compared to the total number of people in the population
Epidemiology: Distribution
Define pattern
Lecture 1
- occurrence of health-related events by time, place, and person
- time may be: annual, seasonal, weekly, daily, hourly, weekday vs weekend, etc.
- place includes: geographic variation, urban/rural differences, location of work sites or schools
- personal characteristics include: age, sex, marital status, SES, behaviors, and environmental exposures
Epidemiology
What are determinants?
Lecture 1
the causes and other factors that influence the occurrence of disease and other health-related events
Specified Populations
Epidemiologist vs. Physicians
Lecture 1
Epidemiologist:
- concerned about the health of the overall population
Physicians:
- concerned about the health of an individual
clinician’s patient is indiviual; epidemiologist’s patient is community
Epidemiology
What is the application of epidemiology?
Lecture 1
it involves applying the knowledge gained by the studies to community-based practice b/c the goal is to prevent disease in the community
John Snow
Who is John Snow?
Lecture 2
An anesthesiologist in the mid 1800s who conducted a series of investigations in London.
- conducted studies of cholera outbreak to discover the cause of disease and how to prevent its recurrence
John Snow: True or False
The father of epidemiology is John Graunt.
Lecture 2
False
John Snow
Breakdown and explain Snow’s first investigation
Broad Sreet Pump
Lecture 2
- A severe cholera epidemic occurred / outbreak
- Snow created a spot map, marking where cholera cases occurred and the locations of water pumps
- He observed patterns and noticed most cases clustered around the Broad Street pump (Pump A)
- Then, he gathered community insights and found out that residents avoided Pump B because it was contaminated and Pump C because it was inconvenient
- To confirm his findings, he investigated anomalies and found that workers at a nearby brewery who drank from a private well did not get cholera and gathered infromation on where people with cholera obtained their water
- Snow formed his hypothesis and conclued that contaminated water from the Broad Street pump was likely the source of the outbreak
- Lastly, he took action by presenting his information to officials and got the pump handle removed
Epidemiology - John Snow
What is descriptive epidemiology?
Lecture 2
describing a health related event in terms of person, place, and time
Epidemiology - John Snow
What is analytic epidemiology?
Lecture 2
measures the association between an exposure and disease
John Snow
What does Snow’s research demonstrate
Lecture 2
- descriptive epidemiology
- hypothesis generation
- hypothesis testing / analytical epidemiology
- application
Epidemiology: Uses
What are the 4 diff uses of epidemiology?
Lecture 2
- Assessing the community’s health
- Making individual decisions
- Completing the clinical picture
- Searching for causes
Epidemiology: Uses
Assessing the community’s health
Explain
Lecture 2
use of data to set goals and monitor progress towards them
- need relevant sources of data
ex: Healthy People 2030
Epidemiology: Uses
Making individual decisions
Explain
Lecture 2
use of epidemiologic information to make daily decisions about health
Epidemiology: Uses
Completing the clinical picture
Explain
Lecture 2
epidemiologists assist physicians in properly diagnosing illness
Epidemiology: Uses
Searching for causes
Explain
Lecture 2
provides substantial evidence to link exposure and illness and effect action
in other words: why did this disease happen
Epidemiology: Core Functions
What are the 6 core functions of epidemiology?
Explain
Lecture 2
- public health surveillance
- field investigations
- analytic studies
- evaluation
- linkages
- policy development
Epidemiology: Core Functions
Public health surveillance
Explain
Lecture 2
ongoing, systemic collection of data to guide decision making and action
goal: to portray patterns of disease to control spread and implement prevention measures
how: morbidity and mortality reports
Public Health Surveillance
What is the difference between active and passive surveillance?
- active: surveillance is on public officials
- passive: other entities report the data
Epidemiology: Core Functions
Field Investigation
Explain
Lecture 2
the process of collecting and analyzing data directly in affected areas to find the source and spread of a disease
also referred to as “shoe leather epidemiology”
Epidemiology: Core Functions
Analytic studies
Explain
Lecture 2
evaluate the credibility of a hypothesis generated from surveillance and field invetigation
Epidemiology: Core Functions
Evaluation
Explain
Lecture 2
determmine relevance, effectiveness, efficiency, and impact in relation to goals
Epidemiology: Core Functions
Linkages
Explain
Lecture 2
connecting public health agencies, laboratories, and healthcare providers to share information and collaborate on disease prevention and response, etc.
Epidemiology: Core Functions
Policy Development
Explain
Lecture 2
creating and implementing public health policies based on data and research to protect and improve community health
Epidemiologic Approach
What does an epidemiologist do?
Lecture 3
- Counts cases or health events, and describes them in terms of time, place, and person
- Divides the number of cases by an appropiate denominator to calculate rates
- Compares these rates over time or for different groups of people
Epidemiologic Approach
Define rate
Lecture 3
the number of cases divided by the size of the population per unit of time
Case definition
What is a case definition?
Lecture 3
a set of standard criteria for classifying whether a person has a particular disease, syndrome or other health condition
Case definition
What are the components of a case defintion?
Lecture 3
- lab tests
- signs (objective)
- symptoms
- time, place, and/or person (outbreak investigations)
True or False
Case definitions are set and do not change.
Lecture 3
False
case definitions may change over time as more information is obtained
Case definition
What are the different types of case definitions?
Lecture 3
sensitive: broad or loose
goal = to capture all true cases
strict: specific
goal = ensure an individual is truly a case
True or False
ALL case definitions require laboratory confirmation
Lecture 3
False
some disease have no distinctive laboratory findings
Epidemiology
What are the 5 W’s of epidemiology?
Lecture 3
- what (health issue of concern)
- who (person)
- where (place)
- when (time)
- why/how (why is this disease occurring and how is it spreading)
Epidemiology
What are the different ways to compile data by time?
Lecture 3
- secular trends (overtime/long term)
- seasonally
- days of the week/time of the day
- epidemic period
Epidemiology
What are the different ways to compile data by geographic extent?
Lecture 3
unit:
- large (continent)
- small (hospital wing)
categorical:
- urban
- rural
state
Epidemiology
What is used to compile data when it comes to people?
Lecture 3
- sex
- ethnicity
- SES
- age
- occupation
- leisure activity
- behaviors
- use of medication
Epidemiology
What is the most important person attribute when compiling data according to the textbook?
Lecture 3
age
Analytic Epidemiology
What is the key feature of analytic epidemiology?
Lecture 3
comparison group
Analytic Epidemiology
What are the two categories of studies that fall under analytic epidemiology?
Lecture 3
- experimental
- observational
Analytic Epidemiology
What are the functions of an experimental study?
Lecture 3
- controlled process determines the exposure for participants
- tracking over time determines the effects of the exposure
ex: placebo
Analytic Epidemiology
What is the function of observational studies?
Lecture 3
to observe the exposure or disease status in participants
Analytic Epidemiology: Observational Studies
What are the 3 types of observational studies?
Lecture 3
- cohort (prospective)
- case control
- cross sectional
Analytic Epidemiology
What are the features of a cohort study?
Lecture 3
- start with exposed individuals (we know the exposure)
- follow individual to see if they develop disease of interest
Analytic Epidemiology
What are the features of a case-control study?
Lecture 3
- investigators enroll a group of participants with a disease (case-patients)
- starts with ill individuals (we are looking for the exposure)
- control group provides an estimate of the baseline or expected amount of exposure in the population
Analytic Epidemiology
What are the features of a cross-sectional study?
Lecture 3
- weakest study because it lacks time aspect but gets a quick idea
- exposures and health statuses of sample population are measured simultaneously
- assesses the prevelance of a health outcome at that point in time without regard to duration
- exposure and outcome are measured at the same time
Analytic Epidemiology
Overall summary
lecture 3
cohort: starts with exposed individuals
case control: starts with ill individuals (back tracking and seeing what exposure led to them being sick)
cross section: measures exposure and disease at the same time
Models of Disease Causation
What are the 3 models of disease causation discussed?
lecture 4
- Rothman’s Pie
- Chain of Infection
- Epidemiologic Triad/Triangle (simplest)
Models of Disease Causation
What does the Epidemiologic Triad consist of?
lecture 4
agent, host, environment
Concepts of Disease Occurrence
Agent
lecture 4
infectious microorganism or pathogen
- virus, bacterium, parasite, or other microbe
- chemical contaminants or physical causes of disease or injury
generally: agent must be present for disease to occur
Concepts of Disease Occurrence
Host
lecture 4
the human who can get the diease
- dependent upon susceptibility, response to an agent
Concepts of Disease Occurrence
Environment
lecture 4
extrinsic factors that affect the agent and the opportunity for exposure
- geology
- climate
- insects transmitting the agent
- socioeconmic factors
Models of Disease Causation
Rothman’s Pie
lecture 4
all pieces of the pie fall into place = disease occurs
- component causes: individual factors (one piece)
- sufficient causes: complete pie (if more pieces come together
- necessary causes: component that occurs in every disease pie (most usually its the bacteria)
Concepts of Disease Occurrence
Natural history
define
lecture 4
the progression of disease in an individual over time in the absence of treatment
timeline could be years
Concepts of Disease Occurrence
Spectrum of disease
define
lecture 4
the range of manifestations and severities of illness associated with given dieases, illness or injury
Infectious Agents
What are the terms for infectious agents?
lecture 4
infectivity: proportion of exposed persons who become infected
pathogenicity: proportion of infected individuals who develop clincally apparent disease
virulence: the proportion of clinically apparent cases that are severe or fatal
Natural History Timeline
What is the timeline for disease?
lecture 4
- stage of susceptibility (exposure occurs)
-
stage of subclinical disease (where pathologic changes occur but individual does not know they are sick; asymptomatic)
in between: onset of symptoms and usual time of diagnosis - stage of clinical disease (symptoms present and individual knows they are sick)
- stage of recovery, disability or death
infectious disease: incubation period
chronic disease: latency period
Chain of infection
What is the chain of transmission?
lecture 4
transmission occurs when the agent leaves its reservoir or host through a portal of exit, is conveyed by some mode of transmission and enters through a portal of entry to infect a susceptible host
Portal of Exit
What is portal of exit?
lecture 4
how the pathogen leaves its host
corresponds to the site where the pathogen is localized
Modes of Transmission
What are the two modes of transmission?
define
lecture 4
direct:
- direct contact (mono)
- droplet spread (sneezing, coughing, etc.)
indirect:
- airbone (infectious agents carried by dust or droplet nuclei suspended in the air; ex: measles)
- vehicle (food, water, biologic products)
- vector (mosquitoes, fleas, ticks, etc.)
Modes of Transmission
Define airbone
lecture 4
infectious agents carried by dust or droplet nuclei suspended in the air
Modes of Transmission
Define vehicle
lecture 4
food, water, biologic products (blood), etc
Modes of Transmission
Define vector
lecture 4
mosquitoes, fleas, ticks, etc.
Portal of Entry
What is portal of entry?
lecture 4
how a pathogen enters a susceptible host
ex: skin, mucous membrane, blood
Disease Control - Chain of Infection
How do we eliminate the agent?
EXAMPLE
lecture 4
antibiotics
Disease Control - Chain of Infection
What methods can help to control the mode of transmission of a disease?
EXAMPLE
lecture 4
- isolation/quarantine
- elimination of the vehicle
Disease Control - Chain of Infection
How can we protect portals of entry?
EXAMPLE
lecture 4
- bed nets
- masks, gloves
Disease Control - Chain of Infection
How can we increase a host’s defense?
EXAMPLE
lecture 4
vaccination
How does the host susceptibility vary?
lecture 4
- genetics differ
- immune/resistant to disease
- lifestyle factors
etc.
Implications for Public Health
What are interventions directed at?
lecture 4
- controlling or eliminating agent
- interrupting the mode of transmission
- protecting portals of entry
- increasing a host’s defenses
Level of Disease
What levels of disease are there?
lecture 4
- sporadic
- endemic
- hyperendemic
- epidemic
- outbreak
- cluster
- pandemic
Level of Disease
Define sporadic
Lecture 4
disease that occurs infrequency/irregularly
- uncommon
- random
- one case/first case
Level of Disease
Define endemic
Lecture 4
amount of disease usually present in a community
- typical cold or flu
- we expect this, its our usual
Level of Disease
Define hyperendemic
Lecture 4
persistent, high levels of disease
- regularly
Level of Disease
Define epidemic
Lecture 4
often sudden increase of cases
Level of Disease
Define outbreak
Lecture 4
often sudden increase of cases in a more limited geographic location
- ex: on stony brook campus vs in state of NY
Level of Disease
Define cluster
Lecture 4
aggregation of cases grouped in place and time suspected to be greated than the number expected
- don’t know why
- unrelated
Level of Disease
Define pandemic
Lecture 4
epidemic spread over several countries or continents
Levels of Disease - Epidemic
Why do epidemics occur?
lecture 4
- agent and host present inadequate numbers
- increase in amount of virulence of agent
- introduction of agent in a setting it has never been before
- enhanced mode of transmission
- change in susceptibility of hosts
- new portals of entry
Epidemic Patterns
What are the type of patterns used to classify epidemics?
classified according to their manner of spread through a population
lecture 4
- common source
- propagated
- mixed
Epidemic Patterns
Define common source
lecture 4
group of persons are all exposed to an infectious agent or a toxin from the same source
point source: group exposed over a relatively brief period (becoming sick in the same incubation period)
continous common source: case-patients exposed over days, weeks, or longer
intermittent common source: irregular pattern of exposure (still from the same source)
Epidemic Patterns
Define propagated
lecture 4
transmission from one person to another; cases occur over more than one incubation period
- direct person-to-person
- vehicle or vectorborne
Organizing Data: Line Listing
What is line listing used for?
lecture 5
used in routine surveillance, investigating an outbreak, conducting a study, etc. to compile information in an organized manner
organized like a spreadsheet with rows and columns
Organizing Data: Line Listing
What makes up a line listing?
lecture 5
row: called a record or observation
- represents one person or case of disease
column: called a variable
- contains information about one characteristic of the individuals (race or date of birth)
Organizing Data: Line Listing
What is a value?
lecture 5
value of a variable is the number or descriptor that applies to a particular person (5’6”, female, never vaccinated, etc.)
- the type of values influence the way in which the variables can be summarized
can be numeric but also can be descriptive + there are four types
Organizing Data: Line Listing
What are the four types of variables?
lecture 5
- nominal-scale variable
- ordinal-scale variable
- interval-scale variable
- ratio-scale variable
Organizing Data: Types of variables
nominal
define
lecture 5
values are categorized without numerical ranking
(ex: ill or well, dead or alive)
Organizing Data: Types of variables
ordinal
define
lecture 5
values are ranked but not necessarily evenly spaced
(ex: stages of breast cancer)
Organizing Data: Types of variables
interval
define
lecture 5
measured on a scale of equally spaced units but without a true zero point (ex: shoe sizes, test scores)
Organizing Data: Types of variables
ratio
define
lecture 5
an interval variable with a true zero (ex: height, age, sickness duration)
Organizing Data: Line Listing
Which variables of the 4 are qualitative variables?
also known as categorical
lecture 5
nominal and ordinal
Organizing Data: Frequency Distribution
Which variables of the 4 are quantitative variables?
also known as continuous
lecture 5
interval and ratio
Frequency Distributions
What is a frequency distribution?
lecture 5
a table or graph that shows how often different values or group of values appear in a dataset
in public health terms: a way of organizing and presenting health related data to show how often a particular health condition, behavior, or characteristic occurs in a population
- helps identify trends, risk factors, and disparities in health outcomes
Frequency Distributions
What are the features/properties of frequency distributions?
lecture 5
- central location
- spread
- shape
- range
Frequency Distributions
What is the Gaussian distribution?
also known as normal distribution
lecture 5
the classic symmetrical bell-shaped curve
- no skew
spread
lecture 5
how widely dispersed a graph is
shape
lecture 5
symmetry
can be symmetrical or asymmetrical (skewed)
Shape: Skewness
positive skew
define
central location is to the left of the tail (tail points to the right)
Shape: Skewness
negative skew
define
central location is to the right of the tail (tail points to the left)
range
lecture 5
measured by spread and distribution
Frequency Distributions: Properties
central location
define
lecture 5
where the graph peaks
there are three measures of central location used in epidemiology: mean, median, and mode
Central Location: Types of Measures
mean
lecture 5
the average value (add up all the numbers and divide by the amount of numbers that are present)
use:
- has excellent statistical properties; commonly used in statistical manipulations and analyses
- called the center of gravity
- affected by any extreme value
Central Location: Types of Measures
median
lecture 5
number in the middle (after being numerically ordered)
use:
- good descriptive measure
- relatively easy to identify
- not often used in statistical manipulations and analyses
- not generally affected by extreme values
Central Location: Types of Measures
mode
lecture 5
number that shows up the most
use:
- preferred measure of central location
- can have one or two more
- used almost exclusively as a descriptive measure
- not affected by extreme values
Investigating an Outbreak
Why would we investigate an outbreak?
lecture 6
- control or prevention of the health problem
- opportunity to learn / research
- public, political, or legal concerns
- public health program considerations
- training
the most important reason is for control and prevention
Investigating an Outbreak
What are the steps of an outbreak investigation?
lecture 6
- prepare for field work
- establish the existence of an outbreak
- verify the diagnosis
- contruct a working case definition
- find cases systemically and record information
- perform descriptive epidemiology
- develop hypotheses
- evaluate hypotheses epidemiologically
- reconsider, refine, re-evaluate
- compare with lab and/or environment studies
- implement control and prevention measures
- initiate or maintain surveillance
- communicate findings
Investigating an Outbreak: Steps (1)
Prepare for field work
define
lecture 6
officials discover an increase in the number of cases of a particular disease and then decide that a field investigation is warranted
-
scientific and investigate issues: must have the appropiate scientific knowledge, supplies, and equipment
- review applicable literature
- assemble useful references (jounrnal articles, sample questionnares)
- know what supplies/equipment to protect yourself
- have a plan of action
-
management and operational issues: must be a good manager and collaborator because most investigations are conducted by a team rather than just one individual
- roles and responsibilities for each members
- communications plan to know how often and when to calls with involved agencies, etc.
- arrange travel, lodging and local transportation
Investigating an Outbreak: Steps (2)
Establish the existence of an outbreak
define
lecture 6
verify that the cases are in fact an outbreak; observed cases compared to the number of expected cases
- outbreak or an epidemic: the occurrence of more cases of disease than expected in a given area or among a specific group of people over a particular period of time
Investigating an Outbreak: Steps (3)
Verify the diagnosis
define
lecture 6
important because you must ensure that the disease has been properly identified since control measures are often disease specific and to rule out laboratory error as the basis for the increase in reported cases
- review clinical findings and lab results
- visit one or more patients with the disease to get a better understanding of clinical features
Helps with generating a hypotheses about disease spread
just like John Snow did with his investigation
Investigating an Outbreak: Steps (4)
Construct a working case defintion
define
lecture 6
includes clinical criteria, and may be restricted by time, place, and person
- diagnosis may be uncertain early on in an investigation. so, cases will be classified as suspected, probable, and confirmed
Investigating an Outbreak: Steps (5)
Find cases & record information
define
lecture 6
public health workers must look for additional cases to determine the true geographic extent of the problem and the populations affected by it
- passive surveillance: sending a letter describing the situation and asking for reports of similar cases (other entities report the data)
- active surveillance: telephoning or visiting the facilities by self to collect information on any additional cases
following data is collected:
- identifying information
- demographic information
- clinical information
- risk factor information
- reporter information (source of the report)
Investigating an Outbreak: Steps (6)
Perform descriptive epidemiology
define
lecture 6
summarizing by time, place, and person
- provides a comprehensive characterization of the outbreak
- infer the population at risk for disease
- provides clues about source, modes of transmission, etc.
- begin thinking about where to begin intervention
helps formulate hypotheses
Investigating an Outbreak: Steps (7)
Develop hypotheses
define
lecture 6
- if the epidemic curve points to a narrow period of exposure, what events occurred around that time?
- why do these people living in one particular area have the highest rate of disease
- why are some groups at greater risk than others?
answers to these questions assist epidemiogists in formulating their hypothesis
Investigating an Outbreak: Steps (8)
Evaluate hypotheses
define
lecture 6
2 ways:
1. compare hypothesis to established facts
2. use analytic epidemiology to quantify relationships:
- retrospective cohort/risk ratio
- case-cohort/odds ratio
Analytic Evaluation (Step 8)
What does a retrospective cohort study consist of?
lecture 6
- small, well-defined population
- exposure and outcomes have already occurred
- calculate the attack rate for those exposed to those not exposed
- calculate risk ratio
Analytic Evaluation (Step 8)
How do you calculate the attack rate?
lecture 6
attack rate = those sick who were exposed/ALL exposed
attack rate = those sick who were not exposed/ALL unexposed
high attack rate among those exposed and low attack rate among those not exposed = exposure is a strong suspect
Analytic Evaluation (Step 8)
What is the method for calculating risk ratio?
lecture 6
attack rate in exposed group/attack rate in unexposed group
Analytic Evaluation (Step 8)
What does a case-cohort consist of?
lecture 6
investigator asks case-patients and controls about their exposures and conducts an odds ratio to quantify the relationship between exposure and disease
controls need to be identified in this study
Analytic Evaluation (Step 8)
What is the method for calculating the odds ratio?
lecture 6
(number of exposed cases x number of unexposed controls) / (number of exposed controls x number of unexposed cases)
or
(AxD)/(BxC)
Investigating an Outbreak: Steps (9)
Reconsider, refine, re-evaluate
define
lecture 6
done in the case that analytic studies do not provide adequate insight
Investigating an Outbreak: Steps (10)
Compare - lab & environmental
define
lecture 6
laboratory evidence can confirm the findings
environmental studies can explain why an outbreak occurred
Investigating an Outbreak: Steps (11)
Control & prevention
define
lecture 6
primary goal: to control outbreak AND prevent additional cases
control measure are usally aimed at segments of the chain of transmission (agent, host, mode of transmission, portal of entry)
Investigating an Outbreak: Steps (12)
Initiate / maintain surveillance
define
lecture 6
once control and prevention measures are implemented, they must be monitored
- this usually comes in the form of active surveillance
questions epidemiologists ask:
- are new cases slowing down or stopping
- are new cases continuing to occur
- where are the new cases, if any
- has the outbreak spread outside the original area where interventions were targeted
Investigating an Outbreak: Steps (13)
Communicate findings
define
lecture 6
oral briefing for local authorities
- in attendance: local health authorities, those responsible for implementing control and prevention measures (epidemiologists)
- investigator describes what they found and recommendations for action
written report
- the usual format (intro, background, methods, etc…)
- this may serve as a reference for health departments encountering a similar outbreak in the future
Measures of RIsk
What is a frequency measure?
lecture 7
characterizes only one part of the distribution to another part of the distribution
consists of: ratios, proportions and rates
Frequency Measures
What is a ratio?
lecture 7
a comparison of any two values
- will always have a fraction
- the numerator and denominator of a ratio can be related or unrelated
ex: you can be comparing apples to oranges
Frequency Measures
What is a proportion?
lecture 7
comparison of a part to the whole
- the numerator is included in the denominator
Frequency Measures
What is a rate?
lecture 7
a measure of the frequency with which an event occurs in a defined population over a specified period of time
- useful for comparing disease frequency in different locations, at different times or among different groups of people with potentially different sized populations
Mortality Requency Measures
What is an infant mortality rate?
lecture 7
number of deaths among children less than one year old
- denominator = number of live births during the same time period
- most commonly used measure for comparing health status among nations
very telling of a how well a country’s population is doing
Rates
Define incidence
lecture 7
occurence of new cases of disease in a population over a specified period of time
Rates
What does incidence describe?
lecture 7
- the probability of developing the disease during a specific period
- describes how quickly a disease occurs in a population
Define prevelance
lecture 7
proportion of persons in a population who have a particular disease or attribute at a specified point in time or over a specificed point in time
- measure used for chronic disease rate
Examples
What is the following fraction an example of:
number of women who have breast cancer in NYS / number of women who have cervical cancer in NYS
lecture 7
ratio
Examples
What is the following ratio an example of:
number of women who have breast cancer in NY / number of women who have any type of cancer in NY
lecture 7
proportion
Examples
What is the following fraction an example of:
number of men who died from lung cancer in NYS in Feb 2025 / number of men living in NYS in Feb 2025
lecture 7
rate
Examples
What is the following fraction an example of:
number of deaths among children less than 1 year of age reported during a given time period x 1,000 / number of live births reported during the same time period
lecture 7
infant mortality rate
Examples
What is the following fraction an example of:
number of women newly diagnosed with heart disease in NYS in 2025 / number of women living in NYS in 2025
lecture 7
incidence
key word: newly
Examples
What is the following an example of:
number of women who have breast cancer in NYS / number of women living in NYS
lecture 7
prevelance
numerator incl. all cases present during given time period NOT JUST NEW
