Chapter 2 Appendix Flashcards
Features of a graph?
most graphs that depict two-variable graphs represent a causal relationship. The shape and orientation of a curve represents the nature of the relationship between both variables.
Implications of Slopes
horizontal and vertical curves mean that the variables are unrelated. Nonlinear curves can have positive/negative, decreasing/increasing curves.
Calculating Slopes
- arc method (2 end points) = average slope.
- point method (tangent) = slope at specific point.
What are numerical graphs?
display numerical data without assuming underlying causal relationships.
Issues with numerical graphs?
- features of construction (size of increments, truncation, % or values)
- omitted variables
- reverse causality
KEY TERM:
Causal Relationship
the relationship between two variables in which the value taken by one variable directly influences or determines the value taken by the other variable.
KEY TERM:
Time-series graph
a two-variable graph that has dates on the horizontal axis and values of a variable that occurred on those dates on the vertical axis.
KEY TERM:
Scatter diagram
a graph that shows points that correspond to actual observations of the x- and y-variables; a curve is usually fitted to the scatter of points to indicate the trend in the data.
KEY TERM:
Pie Chart
a circular graph that shows how some total is divided among its components, usually expressed in percentages.
KEY TERM:
Bar Chart
a graph that uses bars of varying heights or lengths to show the comparative sizes of different observations of a variable.
KEY TERM:
Trucate
some of the ranges of values are omitted.
KEY TERM:
Omitted Variable
an unobserved variable that, through its influence on other variables, creates the erroneous appearance of a direct causal relationship among those variables.
KEY TERM:
Reverse Causality
the true direction of causality between two variables is reversed.
