Intro to Biostatistics Flashcards
Examples of Descriptive statistics include represtation of data in what ways?
Clustered Column
Pie Chart
3-D Column
What is a frequently used graphical display that is often used in medical literature?
- A Study Design Flow Chart
- Kaplan Meier Estimators
- Forest Plots
- Line Graphs
- Histograms
What does inferential Statistics allow researchers to do?
Generalize from our sample of data to a larger group or population
What are inferential statistics used to determine?
The probability that a conclusion based on analysis of the data froma sample is true
What are the measurements based on a sample of population subject to?
Random Error
The ultimate goal of inferential statistis is what?
To be hightly specific about the effect random error has on our sample
What does the ability to estimate how far you might be away from the true value depend on?
2 variables.
What are the 2 variables that the ability to esimate in inferential statistics depends on?
- The sample Size
- The Standard Deviation (SD)
Why is it so important to have a large sample size?
Because the larger the sample size, the greater the likelihood that our estimate will be close to the truth
If there is relatively little variation found about the mean of the sample, whis is likely regarding the sample mean?
It is likeley that the sample mena will lie fairly close to the true value.
What is a variable?
Whatever is being observed or measured
A dependent variable is… ?
The outcome of interest and changes in response to some intervention
(changes in response to the Independent variable)
An independent variable is…?
the intervention or what is being manipulated by the researcher
Explain what a discrete variable is
A discrete variable can have only one of a limited set of values that are whole numbers
What is a continuous variable?
A continous variable can take any value, within a defined range
What is discrete data?
This data has only whole number values
What is continuous data?
This data can take any value within a predetermined range of values
Are many statistical techniques discrete or indiscrete?
Indiscrete
There are 4 types of Data Sprinkles. What are they?
- Nominal
- Ordinal
- Interval
- Ratio
(These can be data or variables)
- Explain what a rate is
- Explain what a proportion is
- What is a percentage?
- A fraction that contains a time component
Ex: 1/1000 people will develop pneumonia this year
- A type of fraction in which the numerator is a subset of the denominator
Ex: 1/3
- A form of proportion where the denominator is artificially set to equal 100
A central or typical value for a propability distribtion (or, an average) is known as what?
Central Tendancy
What is the term for the measure of central tendency for inteval and ratio data?
The mean
- The is the median when talking about central tendency?
- What is an important use of the median?
- It is the value that half of the data points are above and half are below
- It is used as a measure of cntral tendency when the mean would be meaningless, as with ordinal data
Define the “mode” in central tendency
- the only measure that may be used with nominal data
- consists of the most frequenly occuring category.
What is nominal data derived from?
Qualitative measures
Explain what the measure of dispersion is
It refers to how closely the data cluster around the measure of central tendency
What is the term for the difference between the highest and lowest values?
The Range
The variance is what?
It measure how far a set of numbers is spread out
What does a small variance indicate?
that the data points are very close to the mean and each other
Explain what the standard deviation is
- It is the square root of the variance of a random variable or statistical population.
- The SD is expressed in the same usits as the original measurement
The smaller the standard deviation, the closer the numbers are to the ?
mean
