Chapter 1 Flashcards
Element
the entities on which data is collected
ex: students
Variable
A characteristic of interest for the elements
ex: shoe size
Observation
The set of all measurements obtained for a particular element
ex: size 7, blue eyes, 120 lbs
observations = # of elements
Total Data Values
the total number of measurements in a data set
= observations x variables
Experimental Study
A study in which the independent variable is manipulated and the effect on the dependent variable is measured
PROVES causality
Control Variable
A variable that is held constant from one element to the next
AKA: extraneous variables, confounding variables, lurking variables
Observational Study
A study in which the independent variable is NOT manipulated
Does NOT prove causality
Discrete Variable
a variable that can take on a finite number of values within a given interval
only applies to quantitative data
Continuous Variable
a variable that can take on an infinite number of values within a given interval
only applies to quantitative data
Nominal Scale of Data
classification but no hierarchy
ex: color
data type: qualitatitive
Ordinal Scale of Data
definitive hierarchy, but distance between classifications is unknown
ex: military rank
data type: qualitative
Interval Scale of Data
distance between classifications is known, but there is no absolute zero → ratios cannot be calculated
ex: dress size
data type: quanitative
Ratio Scale of Data
Absolute zero exists
ex: weight
data type: quantitative
Qualitative Data
observations take the form of labels or names
nominal & ordinal data
Quantitative Data
observations take the form of numeric values
interval & ratio data
