MEDICAL EPIDEMIOLOGY EXAM
QUESTIONS WITH CORRECT ANSWERS
are Confounding Variables associated with (independent variable/dependent variable/or
both) and what should we do with it if known - ANSWER-The confounding variable may
be associated with either *the independent variable or the dependent variable or both*.
If known they should be taken into account during study design or data analysis.
on what axis on the graph do you have your dependent and independent variables -
ANSWER-dependent variable is on the *y-axis* while independent is on the *x-axis*
what are the ways we measure things in epidemiology - ANSWER-ways we measure
things in epidemiology are
1) count
2) ratio
3) proportion
4) percentage
5) rate
6) unit of exposure
what is count - ANSWER-count is the number of events or individuals or the frequency.
for example, 100 new semester 1 students. Simple count.
what is ratio - ANSWER-a ratio is an assessment that has a numerator and a
denominator. that is A/B. for example The ratio of male AUA students to female AUA
students is: # Male AUA students/# Female AUA students or 200/220
Sometimes we convert a ratio into a ratio per a standard number eg 1000.
Eg the Fetal mortality ratio = (Fetal deaths in a year/Live births in a year) X 1000 -
ANSWER-
what is proportion - ANSWER-Proportion is not the same as ratio. In the proportion the
denominator is everyone or the whole. that is it a A part divided by the whole.
proportion = A/(A+B)
example of proportion - ANSWER-In 2012, there were 3000 deaths in a nation. Of these
300 were due to cardiovascular diseases. Therefore the proportion of deaths attributed
to CV diseases is 300/3000= 0.10 of all deaths were due to CV diseases.
what is percentage - ANSWER-Percentage is a proportion multiplied by 100%.
percentage = [A/(A+B)] X 100
, what is rate - ANSWER-RATE is a measure that expresses rapidity, intensity, velocity or
force of some event; eg new cases of zika virus in a specific time period. it is therefore
*the number of events satisfying specified criteria/Number of units of exposure*
what is the numerator of a rate - ANSWER-The numerator of a rate is the *number of
events or individuals achieving a certain criteria*
what is the denominator of a rate - ANSWER-the denominator of a rate *is the number
of units of exposure examined in counting the numerator.*
what is unit of exposure - ANSWER-Unit of exposure is the passage of an individual
through a certain experience or transition or situation.
for example: person year (a year lived by one person), Pack-years of smoking ( In a
pack year one individual smokes a pack every day for an entire year.)
what are Crude rates - ANSWER-Crude rates are summary stats that ignores
heterogeneity eg Crude birth rate
Crude Birth Rate = Births in a specified year/midyear population in a specific year x
(1000).
What are Specific rates - ANSWER-Specific rates break down the population into
homogenous groups depending on one or more factors. for example
Age specific birth rate= (Births to women of a given age group in a specific year/Midyear
population of women of that age range) x (1000).
what is Incidence and incidence rates - ANSWER-The ratio of the number of new cases
of a disorder or event to the number of potential new cases (people at risk). for example
the number of IV drug abusers newly diagnosed as HIV positive in 2012 is divided by
the number of IV drug abusers in the population during 2012 to yield the incidence rate
for HIV infection among IV drug abusers in 2012.
what is Prevalence and prevalence rates - ANSWER-The number of persons in the
population who have an illness divided by the number of people at risk for the illness.
We can measure point prevalence or period prevalence.
the 2 ways to measure prevalence are________ and _________ - ANSWER-the 2
ways to measure prevalence are *point prevalence* and *period prevalence.*
what is point prevalence - ANSWER-Point prevalence is the number of persons who
have an illness at a specific time point in time divided by the total population who could
potentially have the illness on that date.
what is Period prevalence - ANSWER-Period prevalence is the number of persons who
have an illness during a specific time period divided by the total population who could
have the illness.
QUESTIONS WITH CORRECT ANSWERS
are Confounding Variables associated with (independent variable/dependent variable/or
both) and what should we do with it if known - ANSWER-The confounding variable may
be associated with either *the independent variable or the dependent variable or both*.
If known they should be taken into account during study design or data analysis.
on what axis on the graph do you have your dependent and independent variables -
ANSWER-dependent variable is on the *y-axis* while independent is on the *x-axis*
what are the ways we measure things in epidemiology - ANSWER-ways we measure
things in epidemiology are
1) count
2) ratio
3) proportion
4) percentage
5) rate
6) unit of exposure
what is count - ANSWER-count is the number of events or individuals or the frequency.
for example, 100 new semester 1 students. Simple count.
what is ratio - ANSWER-a ratio is an assessment that has a numerator and a
denominator. that is A/B. for example The ratio of male AUA students to female AUA
students is: # Male AUA students/# Female AUA students or 200/220
Sometimes we convert a ratio into a ratio per a standard number eg 1000.
Eg the Fetal mortality ratio = (Fetal deaths in a year/Live births in a year) X 1000 -
ANSWER-
what is proportion - ANSWER-Proportion is not the same as ratio. In the proportion the
denominator is everyone or the whole. that is it a A part divided by the whole.
proportion = A/(A+B)
example of proportion - ANSWER-In 2012, there were 3000 deaths in a nation. Of these
300 were due to cardiovascular diseases. Therefore the proportion of deaths attributed
to CV diseases is 300/3000= 0.10 of all deaths were due to CV diseases.
what is percentage - ANSWER-Percentage is a proportion multiplied by 100%.
percentage = [A/(A+B)] X 100
, what is rate - ANSWER-RATE is a measure that expresses rapidity, intensity, velocity or
force of some event; eg new cases of zika virus in a specific time period. it is therefore
*the number of events satisfying specified criteria/Number of units of exposure*
what is the numerator of a rate - ANSWER-The numerator of a rate is the *number of
events or individuals achieving a certain criteria*
what is the denominator of a rate - ANSWER-the denominator of a rate *is the number
of units of exposure examined in counting the numerator.*
what is unit of exposure - ANSWER-Unit of exposure is the passage of an individual
through a certain experience or transition or situation.
for example: person year (a year lived by one person), Pack-years of smoking ( In a
pack year one individual smokes a pack every day for an entire year.)
what are Crude rates - ANSWER-Crude rates are summary stats that ignores
heterogeneity eg Crude birth rate
Crude Birth Rate = Births in a specified year/midyear population in a specific year x
(1000).
What are Specific rates - ANSWER-Specific rates break down the population into
homogenous groups depending on one or more factors. for example
Age specific birth rate= (Births to women of a given age group in a specific year/Midyear
population of women of that age range) x (1000).
what is Incidence and incidence rates - ANSWER-The ratio of the number of new cases
of a disorder or event to the number of potential new cases (people at risk). for example
the number of IV drug abusers newly diagnosed as HIV positive in 2012 is divided by
the number of IV drug abusers in the population during 2012 to yield the incidence rate
for HIV infection among IV drug abusers in 2012.
what is Prevalence and prevalence rates - ANSWER-The number of persons in the
population who have an illness divided by the number of people at risk for the illness.
We can measure point prevalence or period prevalence.
the 2 ways to measure prevalence are________ and _________ - ANSWER-the 2
ways to measure prevalence are *point prevalence* and *period prevalence.*
what is point prevalence - ANSWER-Point prevalence is the number of persons who
have an illness at a specific time point in time divided by the total population who could
potentially have the illness on that date.
what is Period prevalence - ANSWER-Period prevalence is the number of persons who
have an illness during a specific time period divided by the total population who could
have the illness.
