1.9 Graphing Data on the Coordinate Plane

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1.9 Graphing Data on the Coordinate Plane

• Two number lines that intersect at right angles
  form a coordinate plane.
• X- axis the horizontal axis
• Y- axis the vertical axis
• Origin where the axes intersect
  (0 , 0)
• Quadrants the four sections of the coordinate
  plane.

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Coordinate Plane
y - axis
( , )
( - , )
Origin (0 , 0)
x - axis
( - , -)
( , -)
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Graphing Points

• An ordered pair of numbers identifies the
  location of a point.
• These numbers are the coordinates of the point on
  the graph.
• (x-coordinate, y-coordinate)
• (-2 , 4)

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Identifying Coordinates
Q
P
W
V
O
Z
T
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Identifying CoordinatesName the coordinates of
each point on the graph.

• Point O
• Point P
• Point Q
• Point T
• Point V
• Point W
• Point Z

• (0 , 0) - origin
• (-4, 1)
• (0 , 2)
• (3 , -3)
• (-1 , 1)
• (4 , 1)
• (-2 , -3)

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Graphing Points

• Graph the point A (3 , -4) on the coordinate
  plane.

A
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Identifying Quadrants

• In which quadrant or on which axis would you find
  each point.
• (-1 , 5)
• Since the x-coordinate is negative, and the
  y-coordinate is positive, the point is in
  Quadrant II.
• b. (0 , 3)
• Since the x-coordinate is 0, the point is on
  the y-axis.

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1.9 Graphing Data on the Coordinate Plane (Cont.)

• 9/29/10
• A scatter plot a graph that relates two groups
  of data.
• Most scatter plots are in the first quadrant of a
  coordinate plane, because the data are usually
  positive numbers.

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Scatter Plot
Year Number of Households With Television (millions)
1950 4
1960 46
1970 59
1980 76
1990 92
2000 101
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Scatter Plots

• Positive correlation in general, both sets of
  data increase together.
• Negative correlation in general, one set of
  data decreases as the other set increases.
• No correlation sometimes data sets are not
  related.
• Trend line shows a correlation more clearly

Negative Correlation
No Correlation
Positive Correlation