AIM: What are some
characteristics of graphs?
Recognize different “classic types of graphs”
Recognize how the manipulated variable (x)
causes a change in the responding variable (y)
AIM: What are characteristics
of
of line graphs?
Best fit graph
Inversely (indirectly) proportional
Directly proportional
• DEFINITION:
•a LINE GRAPH is a diagram which
shows how changing one variable
•(the manipulated variable) X,
•causes a second (or responding)
variable Y to also change in response.
• EXAMPLE: Number of Frog Croaks
Air Temp
# of Croaks per minute
22
12
23
14
24
15
25
16
26
17
31
21
32
26
Step One: Draw your axis:
Step Two: label your axis:
30
20
15
10
22 23 24 25 26 27 28 29 30 31 32
AIR TEMPERATURE Degrees C
Step Three: Plot your Points
30
20
15
10
22 23 24 25 26 27 28 29 30 31 32
AIR TEMPERATURE Degrees C
Step Four: Draw your Line
30
20
15
10
22 23 24 25 26 27 28 29 30 31 32
AIR TEMPERATURE Degrees C
Step Four: Draw your Line
30
20
15
10
22 23 24 25 26 27 28 29 30 31 32
AIR TEMPERATURE Degrees C
Step Four: Draw your Line
30
20
15
10
22 23 24 25 26 27 28 29 30 31 32
AIR TEMPERATURE Degrees C
• Line Graphs: Allow you to estimate trends:
“As temperature increases what is happening to
the number of croaks?”
25
20
15
10
22 23 24 25 26 27 28 29 30 31 32
AIR TEMPERATURE Degrees C
• Line Graphs: Allow you to estimate trends:
“As temperature decreases what is happening to
the number of croaks?”
25
20
15
10
22 23 24 25 26 27 28 29 30 31 32
AIR TEMPERATURE Degrees C
Three Types of Line Graphs
• Best Fit
• Direct
• Indirect
• Line Graphs “Best Fit Graphs”
Normally, best first graphs are only done
when the directions explicitly indicate to
construct a “best fit graph”
Line Graphs:
Inverse Proportional vs. Directly
Proportional Graphs!
GRAPH THIS:
Hours of Study
Grade
.5
50
1
75
1.5
85
2
90
3
100
Grade on Test
Hours of Study vs. Grades
100
80
60
40
20
0
0.5
1
1.5
2
Hours of Study
2.5
3
GRAPH THIS:
Hours of TV
Grade
1
100
2
90
3
85
4
75
5
60
Grade on Test
Hours
Study
vs. Grades
Hours ofofTV
vs. Grades
on Test
100
80
60
40
20
0
1
2
3
4
Hours of TV
5
What is the difference between these two graphs?
Hours
of
Study
vs.
Grades
Hours of TV vs. Grade
Grade on Test
Grade on Test
Hours of Study vs. Grades
100
80
60
40
20
0
0.5
1
1.5
2
2.5
3
Hours of Study
100
80
60
40
20
0
1
2
3
4
5
Hours of TV
As X increases, Y increases
As X increases, Y decreases
Slopes Upward
Slopes Downward
Directly Proportional
Indirectly or Inversely
Proportional
AIM: What is a Line Graph?
Class ACTIVITY:
Creating Line Graphs page 67
Homework:
INTERNET QUESTIONS