1. Section 2.3 Analyzing Graphs HAWKES LEARNING SYSTEMS math courseware specialists Copyright © 2008 by Hawkes Learning Systems/Quant Systems, Inc. All rights reserved.

2. Graphical Descriptions of Data 2.3 Analyzing Graphs HAWKES LEARNING SYSTEMS math courseware specialists 1.Uniform – the frequency of each class is relatively the same. 2.Symmetrical – the data lies evenly on both sides of the distribution. 3.Skewed to the Right – the majority of the data falls on the left of the distribution. 4.Skewed to the Left – the majority of the data falls on the right of the distribution. Shapes of Distribution:

3. Shapes of Distributions (Bluman 5 th Ed. © McGraw Hill) 3 Bluman, Chapter 2

4. Shapes of Distributions (Bluman 5 th Ed. © McGraw Hill) 4 Bluman, Chapter 2

5. Time-series – a picture of how data changes over time. Cross-sectional study – a picture of the data at a given moment of time. Outlier – a data value that falls outside the normal shape of the graph. Definitions: Graphical Descriptions of Data 2.3 Analyzing Graphs HAWKES LEARNING SYSTEMS math courseware specialists

6. Look at the two graphs shown below depicting the same data on people’s satisfaction level with their local shopping mall. Which graph is more accurate and why? Graphical Descriptions of Data 2.3 Analyzing Graphs HAWKES LEARNING SYSTEMS math courseware specialists

7. Misleading Graphs Know the dirty tricks so you won’t be deceived

8. There’s an entire blog! www.forbes.com/sites/naomirobbins She even had a “Bad Graph Contest” http://www.forbes.com/sites/naomirobbins/201 2/05/30/winner-of-the-bad-graph-contest- announced-2/

9. Manipulate the Vertical Axis OriginalVertical axis chopped at top Magnify differences Makes 45% Satisfaction look good.

10. Manipulate the vertical axis OriginalVertical axis extended Everybody seems shorter

11. Manipulate the Vertical Axis OriginalVertical axis chop high & low Distort proportionality

12. Choosing data to create some visual effect and reaction in reader Long historical view of temps http://www.edgeblog.net/wp- content/uploads/2009/10/globaltempchart.gif http://www.edgeblog.net/wp- content/uploads/2009/10/globaltempchart.gif Choose a certain starting year http://zfacts.com/metaPage/lib/zFacts-global- temperature-1860-2005.gif

13. Manipulate the Horizontal Axis OriginalStretch or compress Make slopes (rates of change) look steeper (compress the axis) or more gradual (stretch the axis) Vertical axis design can exaggerate even more http://zfacts.com/metaPage/lib/zFacts-global- temperature-1860-2005.gif http://zfacts.com/metaPage/lib/zFacts-global- temperature-1860-2005.gif

14. Graphic Arts Overkill Plain vertical bar chart

15. Graphic Arts Overkill Fancy 3D and confusing perspectives

16. More web references http://grandgraphs.tumblr.com/ http://flowingdata.com/ – http://flowingdata.com/2012/05/23/venn-pie- agrams/ http://flowingdata.com/2012/05/23/venn-pie- agrams/ – http://flowingdata.com/2012/06/25/chart- chooser-helps-you-choose-charts/ http://flowingdata.com/2012/06/25/chart- chooser-helps-you-choose-charts/