Transcript 1.9 Graphing Data on the Coordinate Plane • Two number lines that intersect at right angles form a coordinate plane. • X- axis.

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.
Coordinate Plane
y - axis
( - , +)
( + , +)
Origin (0 , 0)
x - axis
( - , -)
( + , -)
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)
Identifying Coordinates
Q
P
W
V
O
Z
T
Identifying Coordinates
Name the coordinates of each point on the graph.
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•
•
•
•
•
•
Point O
Point P
Point Q
Point T
Point V
Point W
Point Z
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•
•
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•
•
•
(0 , 0) - origin
(-4, 1)
(0 , 2)
(3 , -3)
(-1 , 1)
(4 , 1)
(-2 , -3)
Graphing Points
• Graph the point A (3 , -4) on the coordinate plane.
A
•
Identifying Quadrants
In which quadrant or on which axis would you
find each point.
a. (-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.
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.
Scatter Plot
Year
Number of Households With Television
(millions)
1950
4
1960
46
1970
59
1980
76
1990
92
2000
101
Television
Households with
Number of
Media in the United States
150
100
50
0
190 195 200 205
0
0
0
0
Year
Series1
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
Positive
Correlation
Negative
Correlation
No Correlation