Types of data and variables Flashcards
What is data?
Measurements of one or more variables made on a sample of individuals
What are the two types of data?
Categorical and numerical
What are the two types of categorical variables?
Nominal and ordinal
What is a categorical variable?
An attribute, something qualitative
What is nominal data?
A name, a membership to a group/category. There is no inherent order
What is ordinal data?
Categorical data that has an order to it, but no magnitude
What is a numerical variable?
Variables that are quantitative and have magnitude
What is continuous data?
The data can be any real number value within a range, including decimals
What is discrete data?
The data are indivisible numerical units that are counts. No decimals
What are two problems with distinguishing categorical from numerical data?
- Discrete values can get analyzed as continuous data if there’s a large number of possible values
- Categorical variables can sometimes be indexed by numbers (1 is presence of trait, 0 is absence)
What is interval data?
Type of numerical data measured along a continuum that has every interval at an equal distance from each other
What is ratio data?
Is a type of interval scale where zero is meaningless and absolute
What are the 4 levels of measurement from least to most sophisticated?
- Nominal
- Ordinal
- Interval
- Ratio
What is a response variable?
The thing that is responding to the other thing
What is an explanatory variable?
The thing that is influencing the other thing, the thing that is being manipulated
What do we do with explanatory and response variables?
Use the explanatory variable to predict/explain a response variable
