Graphing Data on the Coordinate Plane
A coordinate plane is the intersection of two number lines at right angles.
The horizontal line is the x-axis.
The vertical line is the y-axis.
The intersection of the two lines is called the origin.
The coordinate plane is divided into four sections called quadrants.
Ordered pairs identify where a point is located on the coordinate plane
and is written (x, y) with the x-value being the horizontal location from
the origin and the y-value being the vertical location from the origin.
These numbers are the coordinates of the point.
To plot a point on the coordinate plane, begin at the origin. Move
horizontally (left if the x-value is negative or right if the x-value is
positive) to the x-coordinate. From that location, move up (y-value
positive) or down (y-value negative) to the y-coordinate.
Scatter plots are graphs that relate two groups of data. An example of data
that graphs as a scatter plot is the number of calories burned and the time
Scatter plots help find trends in data. There are three types of
relationships possible for two sets of data: positive correlation,
negative correlation, and no correlation.
o Positive correlation – both sets of data increase together
o Negative correlation – both sets of data decrease together
o No correlation – unrelated data sets
To show a correlation more clearly, we use a trend line, which is a line
drawn on a scatter plot that shows the correlation.