7-10 Misleading Graphs
Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes
7-10 Misleading Graphs
Warm Up
Use the graph for Questions 1-3.
1. What network had the
most viewers? ABC
2. What network had the
fewest viewers? FOX
3. What network(s) had
about the same viewer
ship? CBS, NBC
7-10 Misleading Graphs
Problem of the Day
A bar graph has vertical axis intervals of 6.
How would the graph look if the intervals
were twice as large?
It would be half as tall.
7-10 Misleading Graphs
Learn to identify and analyze misleading
graphs.
7-10 Misleading Graphs
A data display that distorts information in order
to persuade can be misleading.
An axis in a graph can be “broken”
to make the graph easier to read.
However, a broken axis can also
be misleading.
In the graph at right, the cost per
minute for service with Company B
looks like it is twice as much as the
cost for service with Company A.
In fact, the difference is only $0.10
per minute.
7-10 Misleading Graphs
Additional Example 1
Both line graphs show the high temperature Monday
through Friday. Which graph could be misleading? Why?
The graph at right could be misleading. It gives
the impression of greater temperature change
because the vertical axis does not begin at zero.
7-10 Misleading Graphs
Check It Out: Example 1
Which graph could be misleading? Why?
Average Restaurant Meal Price
Graph B
20
Price per meal
Price per meal
Graph A
15
10
5
0
Gino’s Village Pasta
Grill
City
City
Diner
25
20
15
10
5
Gino’s Village Pasta
Grill
City
Graph B could be misleading. The vertical axis does not
begin at zero, so differences in scales appear greater.
City
Diner
7-10 Misleading Graphs
Additional Example 2A: Analyzing Misleading Graphs
Explain how you could redraw the graph so it
would not be misleading.
Draw the entire vertical
scale on the graph.
7-10 Misleading Graphs
Additional Example 2B: Analyzing Misleading Graphs
Explain how you could redraw the graph so it
would not be misleading.
Draw the vertical scale with
equal spacing between
marks so that the distance
between 0 and 18,000
equals the distance between
18,000 and 36,000.
7-10 Misleading Graphs
Check It Out: Example 2A
Explain how you could redraw the graph so it
would not be misleading.
Draw the entire
vertical scale on the
graph. The vertical
axis is broken, so
differences in fare
appear greater.
Taxicab Fares
13
12
11
10
Mon Tue Wed Thu Fri
7-10 Misleading Graphs
Check It Out: Example 2B
Explain how you could redraw the graph so it
would not be misleading.
Ounces of Water
Draw the entire
vertical scale on the
graph. The vertical
axis does not start at
zero so differences in
water consumed
seem greater.
Water Consumed
48
40
32
24
16
Mark
Frank
Mila
Yvonne
7-10 Misleading Graphs
Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems
7-10 Misleading Graphs
Lesson Quiz
Explain why each graph could be misleading and
why.
1.
The vertical scale on the
graph is not small enough
to show the changes.
2.
The scale does not start
at 0, so it looks like
fewer people like each
type of animal.
7-10 Misleading Graphs
Lesson Quiz for Student Response Systems
1. Explain why the graph
could be misleading.
A. The vertical axis is broken, so it looks like fewer
people like each type of drink.
B. The vertical scale is not small enough to see
differences.
C. The intervals are not equal to compare the
frequencies.
D. The vertical axis does not begin with zero.
7-10 Misleading Graphs
Lesson Quiz for Student Response Systems
2. Explain why the graph
could be misleading.
A. The vertical axis is broken, so difference in the
number of birds appears smaller.
B. The scale of the graph is not divided into equal
intervals, so differences in the number of birds appear
less than the actual.
C. The vertical scale is not small enough to show the
actual differences.