Pre-Algebra

4-5 Displaying Data

Find the M, M, M, R

9, 6, 117, 5, 7, 6, 8, 8, 7, 9

Mean:

Median:

Mode:

Range:

18.2

7.5

6,7,8,9

112

Pre-Algebra

4-5 Displaying Data

Hours of television

Frequency

0 2

1 3

2 1

3 3

4 0

5 1

Pre-Algebra

4-5 Displaying Data

•A histogram is a type of bar graph. The bars of a histogram represent intervals that the data is grouped. (the bars touch)

Pre-Algebra

4-5 Displaying Data

Money ($) Tally Frequency

0 – 0.99 4

1.00 – 1.99 3

2.00 – 2.99 2

3.00 – 3.99 3

Pre-Algebra

4-5 Displaying Data

Displaying Data in a Line Graph

Make a line graph of the given data. Use the graph to estimate Mr. Y’s salary in 1992.

69,0002000

58,0001995

49,0001990

42,0001985

Salary ($)Year

Pre-Algebra

4-5 Displaying Data

Mr. Y’s 1992 salary was about

Year

Sala

ry

69,0002000

58,0001995

49,0001990

42,0001985

Salary ($)Year

Pre-Algebra

4-5 Displaying Data

What quarter was the percent of all positive plays

Pre-Algebra

4-5 Displaying Data

Pre-Algebra

4-5 Displaying Data

Time Spent at Day Care

Tally Frequency

0:00 to 0:30

0:31 to 1:00

1:01 to 1:30

1:31 to 2:00

2:01 to 2:30

2:31 to 3:00

2:00 1:40 3:00 0:30 1:00 1:30 2:30

0:30 2:45 1:00 2:00 1:35 1:30 3:00

Pre-Algebra

4-5 Displaying Data

Freq

uen

cy

Hours Spent at Day Care

0

1

2

3

4

5

0:00 to0:30

0:31 to1:00

1:01 to1:30

1:31 to2:00

2:01 to2:30

2:31 to3:00

Pre-Algebra

4-5 Displaying Data

Pre-Algebra

4-5 Displaying Data

For example, art is often used to make a graph more interesting, but it can distort

the relationships in the data.

Graphs and statistics are often used to persuade. Advertisers and others

may accidentally or intentionally present

information in a misleading way.

Pre-Algebra

4-5 Displaying Data

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.

Pre-Algebra

4-5 Displaying Data

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.

Pre-Algebra

4-5 Displaying Data

Explain why each graph is misleading.

The scale is so compressed that it’s

hard to see any difference among the

brands.

Pre-Algebra

4-5 Displaying Data

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

Pre-Algebra

4-5 Displaying Data

Explain why each graph is misleading.

140

142

144

146

148

150Preferred 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)

Pre-Algebra

4-5 Displaying Data

Explain why each graph is misleading.

0

20

40

60

80

100

120

Brand X Brand YBrand 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

Pre-Algebra

4-5 Displaying Data

Explain why each statistic is misleading.

A. 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.

B. 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.

Pre-Algebra

4-5 Displaying Data

Explain why each statistic is misleading.

C. 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.

Pre-Algebra

4-5 Displaying Data

Explain why each statistic is misleading.

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.

Pre-Algebra

4-5 Displaying Data

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.

Pre-Algebra

4-5 Displaying Data

Lesson Quiz: Part 1

1.

Explain why each graph or statistic is misleading

Pre-Algebra

4-5 Displaying Data

Lesson Quiz: Part 2

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.”

Explain why each graph or statistic is misleading

Pre-Algebra

4-5 Displaying Data

Lesson Quiz: Part 1

Possible answer: The size of the trucks is larger

than the size of the cars, so it looks like there are as many trucks as cars,

although there are 6 cars and 4 trucks.

1.

Explain why each graph or statistic is misleading

Pre-Algebra

4-5 Displaying Data

Lesson Quiz: Part 2

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.”

The wrecked car’s price brings the average down. Without using the price of the wrecked

car, the average price would be $4750.

Explain why each graph or statistic is misleading