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Best-Fit Line

The line that most closely approximates the data in a scatter plot.

Constant of Variation

The number k in equations of the form y = kx.

Direct Variation

An equation of the form y = kn, where k ≠ 0.

Family of Graphs

Graphs and equations of graphs that have at least one characteristic in common.

Linear Extrapolation

The use of a linear equation to predict values that are OUTSIDE the range of data.

Linear Interpolation

The use of a linear equation to predict values that are INSIDE of the data range.

Line of Fit

A line that describes the trend of the data in a scatter plot.

Negative Correlation

In a scatter plot. as X increases, Y decreases.

Parallel Lines

Lines tin the same plane that never intersect and have the same slope.

Parent Graph

The simplest of graphs in a family of graphs.

Perpendicular Lines

Lines that meet to form right angles.

Point-Slope Form

An equation to the form y-y = m (x - x₁), where M is the slope and (x₁,y₁) is a given point on a non vertical line.

Positive Correlation

In a scatter plot, as X increases, Y increases.

Rate of Change

How a quantity is changing over time.

Scatter Plot

Two sets of data plotted as ordered pairs in a coordinate plane.

Slope

The ratio of change in the y-intercept (rises) to the corresponding change in the x-intercept (run) as you move from one point to another along a line.

Slope-Intercept Form

An equation of the form y = mx+b, where M is the slope and B is the y-intercept.