Term

Definition
a quantity that can take on more than one value 


Term

Definition
exists between two variables when the value taken by one variable directly influences or determines the value taken by the other variable. 


Term

Definition
if the curve is a straight line, the variables have a linear relationship 


Term

Definition
if the curve is not a straight line, the variables have a nonlinear relationship 


Term

Definition
when an increase in the value of one variable is associated with an increase in the value of the other variable. It's illustrated by a cure that slopes upward from left to right 


Term

Definition
when an increase in the alue of one variable is associated with a decrease in the value of the other variable. It's illustrated by a curve that slopes downward from left to right. 


Term

Definition
the horizontal intercept of a curve is the point at which it hits the horizontal axis; it indicates the value of the xvariable when the alue of the yvariable is zero 


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Definition
the point at which the curve hits the vertical axis; it shows the value of the yvariable when the value of the xvariable is zero 


Term

Definition
the slope of a line or curve is a measure of how steep it is. The slope of a line is measured by "rise over run" the change in the yvariable between two points on the line divided by the change in the xvariable between those same two points



Term

Definition
is one in which the slope is not the same between every pair of points 


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Definition
the value of a negative number without the minus sign 


Term

Definition
a straight line that just touches, or is tangent to, a nonlinear curve at a particular point. The slope of the tangent line is equal to the slope of the nonlinear curve at that point 


Term

Definition
a nonlinear curve may have a maximum point, the highest point along the curve. At the maximum, the slope of the curve changes from positive to negative. 


Term

Definition
a nonlinear curve may have a minimum point, the lowest point along the curve. At the minimum, the slope of the curve changes from negative to positive. 


Term

Definition
has dates on the horizontal axis and values of a variable that occured on those dates on the vertical axis 


Term

Definition
shows points that correspond to actual observations of the x and yvariables. A cure is usually fitted to the scatter of points 


Term

Definition
shows how some total is diided among its components, usually expressed in percentages 


Term

Definition
uses bars of varying height or length to show the comparative sizes of different observations of a variable 


Term

Definition
an axis is truncated when some of the values on the axis are omitted, usually to save space 


Term

Definition
an unobserved variable that, through its influence on other variables, creates the erroneous appearance of a direct causal relationship among those variables 


Term

Definition
an error committed when the true direction of causality between two variables is reversed 

