©Cynthia Krebs, ISYS 3270©Cynthia Krebs, ISYS 3270

Understanding

Charts and

Graphs

Understanding

Charts and

Graphs

“Empowered as the new gods of cyberspace, we have been granted the ability to devour megabytes of data at a single gulp, digest it in mere microseconds and spew it forth without further thought as visually stunning color imagery. Gerald E. Jones, How to Lie with Charts

Charts display facts or numerical information in an organized way. Flowcharts, maps, lists, and diagrams are examples of charts.

Graphs use numerical information to show relationships, comparisons, or change.

The terms charts and graphs are interchangeable.

What are charts and graphs?What are charts and graphs?

Benefits of Charts and GraphsBenefits of Charts and Graphs

Data is more understandableInformation is summarized Trends become apparentNumeric relationships are clarified

Data is more understandableInformation is summarized Trends become apparentNumeric relationships are clarified

A picture is worth a thousand words!

Creating a Chart Involves:Creating a Chart Involves:

Examining the dataDefining the purposeChoosing the right chart typeEntering the data or importing it from other applications Editing the chart data

Examining the DataExamining the Data

What type of information are you trying to illustrate?What message do you want to emphasize?Will a chart/graph clarify or cloud your message?

Ask:Ask:

Basic Chart ElementsBasic Chart Elements

$0$10$20$30$40$50$60$70$80$90

(In

Mill

ions

)

1999 2000 2001 2002

Annual Sales

OgdenSLCProvo

Title

X-Axis Label

X-Axis

Y-Axis

Y-AxisLabel

Legend

20

31

46

27

3947

90

35

45

20

32

44

$0

$20

$40

$60

$80

$100

(In

Mill

ions

)

1999 2000 2001 2002

Annual Sales

Ogden

SLC

Provo

Additional Chart ElementsAdditional Chart Elements

Scale

Tick marks

Gridlines

Data labels

Series

Defining Your PurposeDefining Your Purpose

What are the variables?Can you make comparisons?Are you showing change over time?Does one event predict another?Is there a relationship in the data?

Choosing the Chart Type Choosing the Chart Type

Grow, decline, trendsLine charts, column charts

Ranks or comparesBar charts

Percentage, portion, sharePie charts

Look for key words:Look for key words:

TablesTables

Show exact numbers or textArrange data in columns and rowsDisplay data in a small space

LodgingComparison

LodgingComparison

Lodging # Rooms Dining Pool Pets

Sleep’n Inn 30 Super 6 119

Best Motel 133 Valley View 200

Use color in a cell, row, or column for emphasis

Column GraphsColumn Graphs

Show trends or changes over timeDisplay limited number of data points Arrange time data chronologically left to right

0102030405060708090

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West

North

Line GraphsLine Graphs

Show trends or changes over timeShow forecasts and projectionsDetail many data pointsConnect data point with trend lines

0102030405060708090

100

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Area GraphsArea Graphs

Show the magnitude of trends or changes over timeDisplay the area below the plot line as a solid objectMay hide data

0

10

20

30

40

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East

West

PictographsPictographs

Illustrate concepts onlyUse pictures or symbols instead of barsSelect pictures that suggest graph subjectShows comparisons

0 10 20 30 40

Air

Land

Pie ChartsPie Charts

Compare relative parts to the wholeDisplay as a circle broken into segments

1st Qtr2nd Qtr

3rd Qtr4th Qtr

Donut ChartsDonut Charts

Compare the percentages of several different seriesResemble a set of concentric, hollowed-out pie charts

Toys

Games

Sporting Goods

XY or Scatter GraphsXY or Scatter Graphs

Compare pairs of values, shows relationshipsUse two coordinates for each pointDisplay patternsDiscrete values where data points coincide along the X and Y axes

22.227.4

90

20.430.6

38.6 34.6 31.6

45.9 46.9 45 43.9

0102030405060708090

100

0 2 4 6

EastWestNorth

Surface ChartsSurface Charts

Show trends in values across two dimensionsDisplay on a surface that rises and falls to emphasize peaks and valleys

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East

80-10060-8040-6020-400-20

Radar ChartsRadar Charts

Display data radiating from the center Compare trends and magnitudes relative to a center point

0

50

1001st Qtr

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Bubble ChartsBubble Charts

Show the relationship of sets against timeCompare three sets of valuesDisplay third value as size of bubble

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120

0 2 4 6

EastNorth

Stock of Hi/Low/Close ChartsStock of Hi/Low/Close Charts

Display daily high, low, open ,and close valuesUse the ends of the vertical line to indicate the high and low valuesUse the horizontal lines to indicate the close values

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100

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

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Mixed ChartsMixed Charts

Combines two series types for the data.

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100

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

WestEast

Interpreting Charts and GraphsInterpreting Charts and Graphs

Read titles, labels, and legendLook at numerical valuesStudy data

Make comparisonsLook for relationshipsCheck for trends

Draw conclusions Click for USA Today Snapshots

Data charts provide a visual interpretation of data so you can

give your audience a clear picture of the point you are communicating.

Data charts provide a visual interpretation of data so you can

give your audience a clear picture of the point you are communicating.

0

10

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80

90

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

EastWestNorth