Warm Up

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Warm Up
Problem of the Day
Lesson Presentation
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Warm Up Use the data below to answer each
question. 20 21 23 24 27 33 34 35 36
38 40 41 42 43 46 52 53 1. What is the
median? 2. What is the mode? 3. What is the
range?
36
none
33
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Problem of the Day Nine students in a group
found that their mean score was 86 for the first
math test. On the next test, each student in the
group scored 7 points higher than on the first
test. What was their mean score for the two tests?
89.5
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Learn to recognize misleading graphs.
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Additional Example 1A Misleading Bar Graphs
Why is this bar graph misleading?
Because the lower part of the vertical axis is
missing, the differences in prices are
exaggerated.
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Additional Example 1B Misleading Bar Graphs
What might people believe from the misleading
graph?
People might believe that Cars B and C cost 1
to 2 times as much as Car A. In reality, Cars B
and C are only a few thousand dollars more than
Car A.
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Check It Out Example 1A
Money Raised
600
580
570
560
Dollars
550
540
530
4th graders 5th graders 6th graders
Why is this bar graph misleading?
The vertical axis begins at 530 rather than 0.
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Check It Out Example 1B
Money Raised
600
580
570
560
Dollars
550
540
530
4th graders 5th graders 6th graders
What might people believe from the misleading
graph?
That the 5th graders have raised twice as much
money as the 4th graders.
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Additional Example 2A Misleading Line Graphs
Why are these graphs misleading?
If you look at the scale for each graph, you will
notice that the April graph goes from 54 to 66
and the May graph goes from 68 to 80.
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Additional Example 2B Misleading Line Graphs
What might people believe from these misleading
graphs?
People might believe that the temperatures in May
were about the same as the temperatures in April.
In reality, the temperatures in April were about
15 degrees lower.
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Additional Example 2C Misleading Line Graphs
Why is this line graph misleading?
The scale goes from 0 to 80, and then increases
by 5.
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Check It Out Example 2A
November
September
Temperature (F)
Temperature (F)
Week
Week
Why are these graphs misleading?
If you look at the scale for each graph, you will
notice that the September Graph goes from 85 to
70 and the November graph goes from 65 to 50.
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Check It Out Example 2B
November
September
Temperature (F)
Temperature (F)
Week
Week
What might people believe from these misleading
graphs?
People might believe that the temperatures in
September were about the same as the temperatures
in November. In reality, the temperatures in
September were about 20 degrees higher.
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Check It Out Example 2C
Corp. C Corp. D
Stock prices
80
70
Price of stock ()
60
50
0
1985 1990 1995 2000
Year
Why is this line graph misleading?
The scale goes from 0 to 50, and then increases
by 10.
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Lesson Quiz
1. Why might this line graph be misleading?
2. What might people believe from the
graph?
The scale does not start at zero.
Possible answer that there were hardly any
visitors on Monday