9-6 Misleading Graphs and Statistics

Course 3

Warm UpProblem of the DayLesson Presentation

Warm Up

1. How many students say oranges are their favorite?

2. What is the least popular fruit?

3. How many students answered the survey?

40

Kiwi

90

Course 3

9-6 Misleading Graphs and Statistics

Use the graph for problems 1-3

Problem of the DayCreate a data set with five values that will have a mean of 20, a median of 18, and a mode of 15.Possible answer: 15, 15, 18, 19, 33

Course 3

9-6 Misleading Graphs and Statistics

Learn to recognize misleading graphs and statistics.

Course 3

9-6 Misleading Graphs and Statistics

Course 3

9-6 Misleading Graphs and Statistics

Graphs and statistics are often used to persuade. Advertisers and others may accidentally or intentionally present information in a misleading way.

Course 3

9-6 Misleading Graphs and Statistics

Additional Example 1A: Identifying Misleading Graphs

Explain why each graph is misleading.

The graph suggests that the stock will continue to increase through 2020, but there’s no way to foresee the future.

Course 3

9-6 Misleading Graphs and Statistics

Additional Example 1B: Identifying Misleading Graphs

Explain why each graph is misleading.

Because the scale leaves out 0 to 100, the bar heights make it appear that the sixth grade sold about three times as many tickets as either of the other two grades. In fact, the sixth grade sold only about 20% more.

Course 3

9-6 Misleading Graphs and Statistics

Additional Example 1C: Identifying Misleading Graphs

Explain why each graph is misleading.

The scale is so compressed that it’s hard to see any difference among the brands.

Check It Out: Example 1A

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Course 3

9-6 Misleading Graphs and Statistics

Explain why each graph is misleading.

0

10

20

30

40

50

60

1 2 3 4 5* 6* * projected

% of Return on Investment

The graph suggests that the rate of investment return will continue to increase, but there are no guarantees

Check It Out: Example 1B

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Course 3

9-6 Misleading Graphs and Statistics

Explain why each graph is misleading.

140142144146148150

Preferred Juice Flavors

Grape Cherry Apple

The graph appears to indicate that significantly more people prefer grape drink over the others when in fact there is a small margin of difference. (0 to 140 is not graphed)

Check It Out: Example 1C

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Course 3

9-6 Misleading Graphs and Statistics

Explain why each graph is misleading.

020406080100120

Brand X Brand Y Brand Z

Drink Sales This graph is too compressed to see much difference between the brands indicating that they are fairly equal.

No data from 50 to 120

Course 3

9-6 Misleading Graphs and Statistics

Additional Example 2: Identifying Misleading Statistics

Explain why each statistic is misleading.A. Four out of five dentists surveyed preferred UltraClean toothpaste.

This statement does not give the sample size or state what UltraClean toothpaste was compared with.

B. Shopping at Save-a-Lot can save you up to $100 a month!

The words save up to $100 mean that the maximum you can save is $100, but there is no guarantee that you will save that amount.

Course 3

9-6 Misleading Graphs and Statistics

Additional Example 2: Identifying Misleading Statistics

Explain why each statistic is misleading.

C. Sam scored 43 goals for his soccer team during the season, and Jacob scored only 2.

Although Jacob scored only 2 goals, he may have played most of his time on defense.

Explain why each statistic is misleading.Check It Out: Example 2

Course 3

9-6 Misleading Graphs and Statistics

A. Four out of five breeders recommend Pet Blend dog food for a healthier coat.This statement does not give the sample size or state what Pet Blend dog food was compared with.

B. Fruity Squares makes the cereal 100% more fun.

You cannot measure how much fun Fruity Squares makes the cereal.

Course 3

9-6 Misleading Graphs and Statistics

Explain why each statistic is misleading.C. The total revenue for bathing suits sold in May

at Worthman’s Florida stores is 250,000. The total revenue for bathing suits sold in May at Worthman’s North Dakota stores is 10,000.

The states have different populations and climates.

Check It Out: Example 2

Lesson Quiz: Part I

Possible answer: The difference in size between the car and truck symbols distorts the comparison.

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Course 3

9-6 Misleading Graphs and Statistics

1.

Explain why each graph or statistic is misleading

Lesson Quiz: Part II

2. A budget area of a used-car lot has five cars on it, with prices of $4200, $4700, $4900, $5200, and $900 (a wrecked one). The car ad in the local paper reads “Average priced car on budget lot is $3980.”

A low outlier was included in order to bring down the average cost.

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Course 3

9-6 Misleading Graphs and Statistics

Explain why each graph or statistic is misleading