Exam #1: Biostatistics I Flashcards
What are the six major reasons to study stats as a medical student?
1) To evaluate medical lit.
2) To communicate w/ patients
3) To communicate w/ peers
4) To evaluate your performance
5) To protect your practice from the MISuse of statistics
6) Conduct your own investigation
Where the two major divisions of the field of statistics?
- Descriptive
- Inferential
What is the purpose of descriptive statistics & what does the field involve?
Purpose is to describe data, which involves:
- collecting data
- presenting data
- characterizing data
What is the purpose of inferential statistics & what does the field involve?
Purpose is to make decisions about population characteristics, which involves:
- Estimation
- Hypothesis testing
****This field uses the descriptive stats to make generalizations about the underlying population
What are experimental elements or units of analysis?
Objects upon which we collect data
What is the population?
All of the items of interest
*****Measurements that are based on a population are called “parameters.”
What is a variable?
Characteristic of an individual experimental unit
What is a sample?
Subset of the units of a population
******Measurements that are based on a sample are called “statistics.”
What is the difference between a categorical & quantitative variable?
Categorical= a numeric or character code that represents
- Presence or absence of trait
- Relative weight/ rank of thing being studied
Quantitative= numerical result of some measurement
What are the four scales of measurement?
1) Nominal scale*
2) Ordinal scale*
3) Interval scale**
4) Ratio**
*Categorical
**Quantitative
What is the nominal scale?
Categories observations e.g. male v.s. female
What is the ordinal scale?
Nominal variables that have an order or rank e.g. cancer stage
What is an interval scale?
Measurable difference between two observations e.g. temperature
What is a ratio?
Same as interval but with an absolute reference point
How are qualitative variables described/ presented?
Summary tables/ graphs
Write the symbols for mean for both sample and a population.
Write the symbols for size for both sample and population.
Draw the standard notation for standard deviation & variance for samples & populations.
