Variables of Data Flashcards
Types of qualitative data
Nominal
Ordinal
Types of quantitative data
Discrete
Continuous
Types of continuous data
Interval
Ratio
What does variable refer to?
Anything that is measured or observed or manipulated in a study
What is nominal data?
Named categories
What is binary data?
Nominal data with just two categories
What is ordinal data?
Set of ordered categories
When is quantitative data said to be discrete?
If values of measurement are integers i.e. whole numbers
What is interval data?
Measurements where difference between two values is meaningful
What is ratio data?
They have all the properties of interval variable and also have a clear definition of zero points, so ratios are meaningful
Examples of ratio variables
Height
Weight
What can one calculate from nominal data?
Mode (frequency)
What can one calculate from ordinal data?
Mode
Median
What can one calculate from interval data?
Mode
Median
Sum/diferences
Mean
What can one calculate from ratio data?
Mode
Mean
Sum/differences
Mean
Ratios
What is the independent variable?
Controlled by experimenter
Presumed to have causal/antecedent effect on dependent variable
What is dependent variable?
Depends on value of independent variable
What is mediator variable?
One which mediates the effects of A causing B
What is a complete mediator?
One without which A cannot cause B
What is a partial mediator?
One which when absent, reduces but does not eliminate effect of A on B
What is statistical mediation?
How C mediates the effects of A causing B
How can the effects of mediators be statistically analysed?
Using regression tests
How are nominal and ordinal data analysed?
Nonparametric tests
How are most measured variables analysed?
Parametric tests
