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
Cross-Sectional Data
data collected at one point in time
often used to compare the subjects
Time Series Data
data that is collected on the same subjects over several points in time
AKA: longitudinal data
Cyclical Effect
any consistent variation in daily, weekly, monthly, or annual data
ex: the number of people on the T consistently fluctuates based on the time of day
Seasonal Effect
any change in the data that can be explained by annual, calendar-related events
ex: retail store sales increase from November - December
Irregular Effect
a change in the data that is not related to a cycle or season
ex: The Dow Jones drop in March 2020
