Biostatistics Final Exam Questions and Answers 2023 with
complete solution
What is biostatistics?
Discipline concerned with the treatment and analysis of numerical data derived from
biological, biomedical, and health-related studies.
What is measurement?
How we get our data... the assignment of numbers of codes according to prior set-rules
What are the three disciplines of biostatistics?
1. Improve intellectual content of data.
2. Organize data into a format that is understandable.
3. Relies on tests of experience as standard of validity.
What is an observation? example?
The unit upon which a measurement is made. ex: a person or a region.
What is a variable?
A characteristic being measured.
What is a value?
A number or code that has been realized
How do you set up a data table?
Observations in rows
Variables in columns
Values in the middle
When would you use a categorical scale? Example?
When there are two or more categories with no intrinsic ordering to the categories.
Example - gender, blood type, disease state.
When would you use an ordinal scale? Example?
it puts observations into categories that can be ranked/ordered. Ex: cancer stages.
When would you use a quantitative scale? Example?
For numeric values. Ex: height, weight, age.
What is objectivity?
The intent to measure things as they are without shaping them to conform to a
preconceived worldview.
What are the two forms of measurement errors?
1. Imprecision
2. Bias
What is imprecision?
The Inability to get the same result on repeat.
What is reliability?
Ability to replicate.
What is bias?
The tendency to overestimate or underestimate the true value.
What is validity?
The ability to identify the true nature of observation... when something is unbiased
What are two types of studies?
, Survey
Comparative (experimental and non experimental)
What kind of sample entails equal chance in selection for generalization to the
population?
Simple random sample.
What are three cautions you must have when picking a sample?
Undercoverage
Volunteer bias
Non response bias
What is undercoverage?
Groups in population are left out or underrepresented.
What is non response bias?
Large percentage of sample refuse or can't be contacted.
What is a probability sample?
Sample in which each member of the population has a known probability of being
selected int the sample.
What is a stratified random sample?
It draws independent SRS from within a relatively homogenous group.
Ex - divide the population into 5 year age groups and SRS within that
What is a cluster sample?
Randomly selects large units with smaller subunits.
What is probability?
The proportion of times an event is expected to occur in the population - useful for
predicting future outcomes.
What is the explanatory variable?
The treatment or exposure that explains or predicts changes in the response variable.
What is the response variable?
The outcome or response being investigated
What is confounding?
A distortion in an association between an explanatory variable and response variable
brought about by the influence of extraneous factors.
What is an interaction?
Factors in combination produce an effect that could not be predicted by looking at the
effect of each factor separately.
What is blinding? What are the types?
Technique where individuals in the study are kept unaware of the treatment
assignments
Single - subject unaware
Double - subject and investigator unaware
Triple - subject, investigator, and statistician unaware
What is equipoise?
The balance of doubt versus benefits and risks for a study.
What do you have to make sure to add at the bottom of your stem and leaf plot?
The axis multiplier
complete solution
What is biostatistics?
Discipline concerned with the treatment and analysis of numerical data derived from
biological, biomedical, and health-related studies.
What is measurement?
How we get our data... the assignment of numbers of codes according to prior set-rules
What are the three disciplines of biostatistics?
1. Improve intellectual content of data.
2. Organize data into a format that is understandable.
3. Relies on tests of experience as standard of validity.
What is an observation? example?
The unit upon which a measurement is made. ex: a person or a region.
What is a variable?
A characteristic being measured.
What is a value?
A number or code that has been realized
How do you set up a data table?
Observations in rows
Variables in columns
Values in the middle
When would you use a categorical scale? Example?
When there are two or more categories with no intrinsic ordering to the categories.
Example - gender, blood type, disease state.
When would you use an ordinal scale? Example?
it puts observations into categories that can be ranked/ordered. Ex: cancer stages.
When would you use a quantitative scale? Example?
For numeric values. Ex: height, weight, age.
What is objectivity?
The intent to measure things as they are without shaping them to conform to a
preconceived worldview.
What are the two forms of measurement errors?
1. Imprecision
2. Bias
What is imprecision?
The Inability to get the same result on repeat.
What is reliability?
Ability to replicate.
What is bias?
The tendency to overestimate or underestimate the true value.
What is validity?
The ability to identify the true nature of observation... when something is unbiased
What are two types of studies?
, Survey
Comparative (experimental and non experimental)
What kind of sample entails equal chance in selection for generalization to the
population?
Simple random sample.
What are three cautions you must have when picking a sample?
Undercoverage
Volunteer bias
Non response bias
What is undercoverage?
Groups in population are left out or underrepresented.
What is non response bias?
Large percentage of sample refuse or can't be contacted.
What is a probability sample?
Sample in which each member of the population has a known probability of being
selected int the sample.
What is a stratified random sample?
It draws independent SRS from within a relatively homogenous group.
Ex - divide the population into 5 year age groups and SRS within that
What is a cluster sample?
Randomly selects large units with smaller subunits.
What is probability?
The proportion of times an event is expected to occur in the population - useful for
predicting future outcomes.
What is the explanatory variable?
The treatment or exposure that explains or predicts changes in the response variable.
What is the response variable?
The outcome or response being investigated
What is confounding?
A distortion in an association between an explanatory variable and response variable
brought about by the influence of extraneous factors.
What is an interaction?
Factors in combination produce an effect that could not be predicted by looking at the
effect of each factor separately.
What is blinding? What are the types?
Technique where individuals in the study are kept unaware of the treatment
assignments
Single - subject unaware
Double - subject and investigator unaware
Triple - subject, investigator, and statistician unaware
What is equipoise?
The balance of doubt versus benefits and risks for a study.
What do you have to make sure to add at the bottom of your stem and leaf plot?
The axis multiplier
