Download Coordinates and Scatter Plots

4.1
Coordinates and Scatter Plots
• Objective 1 – Plot points in a
coordinate plane
• Objective 2 – Draw a scatter plot
and make predictions about real
life situations
•A coordinate plane is formed by two real number lines that
intersect at a right angle
•Each point in the plane corresponds to an ordered pair of real
numbers (x, y)
y
• The first number in an
ordered pair is the
x – coordinate
vertical or y axis
• The second number in an
ordered pair is the
y – coordinate
• The ordered pair (3, -2)
has an x – coordinate of 3
and a y – coordinate of -2
horizontal
or x axis
x
O
origin
(0,0)
(3, -2)
(5, 4)
Quadrant II
Quadrant I
(-, +)
(+, +)
(0, -2)
Quadrant III
Quadrant IV
(-, -)
(+, -)
EXAMPLES Plotting Points in a coordinate
Plane
1.
2.
3.
4.
5.
(3, 4)
(-2, -3)
(2, 0)
(-5, 2)
(0, 4)
y
1. (3, 4)
2. (-2, -3)
(0, 4)
(3, 4)
(-5, 2)
3. (2, 0)
x
(2, 0)
4. (-5, 2)
5. (0, 4)
(-2, -3)
Winter Sports Equipment
Year
1990
1991
1992
1993
1994
1995
1996
Snowboards
322
362 391 515 715 924 970
Skis
606
577 627 611 652 607 644
a) Draw a scatter plot for each set of data in
the same coordinate plane
b) Describe the pattern of the amount spent
on Snowboards
c) Describe the pattern of the amount spent
on Skis
a)
Scatter plot
Amount spent (millions of $)
Winter Equipment
1200
Snowboards
1000
800
600
Skis
400
200
0
1990
1991
1992
1993
1994
1995
1996
Years
b)
c)
Amount spent on Snowboards has been increasing
Amount spent on Skis has been mostly constant
1997
A
25
B
20
20
15
15
10
10
5
5
25
0
0
0
1
2
3
4
5
6
7
8
9
10
11
C
0
1
2
3
4
5
6
7
8
9
A. Positive Correlation
18
16
14
B. Negative Correlation
12
10
C. No Correlation
8
6
4
2
0
0
1
2
3
4
5
6
7
8
9
10
11
10
11