Presenting Statistics in Social Media

Or You Can Lie With Statistics but it’s a Lot Easier with Words

Everything is NumbersStatistics are used to estimate & describe

patterns in nature that aren’t easy to see with the naked eyeSports-Earned Run Average, Slugging

Percentage, QB Rating, Goals Against AverageEconomics-Gross Domestic Product,

Unemployment, InflationMedicine-Heart Rate, % Body Fat, T-Cell

CountsEducation-IQ Scores, SAT scores, Dropout

RatesAs long the statistic is from a source of data

that is verifiable, it’s hard to lie using it.

Types of StatisticsMeasures of Central Tendency (aka Averages)

Continuous-Number can take any value. Mean (sum of all data divided by the number of data

points) Median (midpoint of all data when it is ranked from

highest to lowest) Mode (most frequently occurring data value)

Discrete-Value can only take certain values eg. 0 or 1, true or false. Proportion-sum of values taking a certain value for

a given variables divided by the maximum value for that variable.

Types of Statistics (cont.)Measures of Spread

Range-highest data value-lowest data value Variance-Average squared deviation from the mean Standard Deviation-square root of the variance

ProbabilityUsed to measure the chance of eventsAlso used to make a statement about the

relationship between a sample and a population that it’s taken from eg. margin of error.

But a Summary Statistic can Never Tell You the Whole StoryGraph with States Graph without States

Graph TypesBar Graph-Good visually but not good for trends

Line Graph-Better for showing trends over time

time 1

time 2

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Product AProduct BProduct C

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40

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Product AProduct BProduct C

Graph Types (Cont)This is the first pie chart created by Florence Nightingale to show the number of British soldiers in the Crimean War who died due to infection rather than combat injuries.

Graph Types (cont.)Mapping using Geographical Information Systems (GIS) is a good way to represent data by region. In this graph I showed which areas of the city have the highest number of crimes by census tract in the city for 2005.

Posting Graphs on the WebLine, Bar, Pie, & other Graphs can be created

using Microsoft Excel, SPSS, SAS, ArcGIS, R, & other Packages

If that data package will allow you to save that graph as a .jpg, .gif, or .png file you can easily add it to your blog.Microsoft Excel requires a visual basic

command to save graphs as image files.

Statistical PackagesMicrosoft Excel-Most readily available but

not really built for statistical analysis. OK to make basic graphs.

SPSS-Better for more advanced analysis and graphics but less accessible due to cost. User friendly.

R-Free software package that can be downloaded from the web. Can do many types of analyses. BUT it is syntax driven. Can save graphics as image files using syntax.

Cutting Edge GraphicsThe Gapminder institute provides great

interactive graphics for free that can be seen in the documentary the Joy of Stats.URL: www.gapminder.orgJoy of Stats Clip:

http://csiwodeadbodies.blogspot.com/2010/12/income-and-life-expectancy-what-does-it.html

The website Fractracker uses advanced graphics and mapping techniques to monitor the impacts of Marcellus Shale drilling in Pennsylvania and New York.URL: http://www.fractracker.org/

Poor Statistical Reasoning ExampleThe blog The Audacious Epigone posted an

analysis of the IQ’s of a sample of McCain & Obama voters which can be seen at http://anepigone.blogspot.com/2011/05/iq-wars-mccains-voters-win.html

Some Good Statistical BlogsFiveThirtyEight-Nate Silver’s blog which

forecasts elections, the Oscars, and other sporting events. http://fivethirtyeight.blogs.nytimes.com/

Data Visualisation-Has more examples of cutting edge graphics. http://www.datavis.ca/

The Incidental Economist-Good Analysis of health care data. http://theincidentaleconomist.com/wordpress/

CSI without Dead Bodies-My own websitehttp://csiwodeadbodies.blogspot.com

Sources of Data on the WebMany websites, such as The Census Bureau’s

provide data for download with which to do your own analysis.Example-Small Area Health Insurance Estimates

(SAHIE) makes state and county level estimates for the whole US from 2005-2007 (2008 and 2009 estimates are forthcoming) http://www.census.gov/did/www/sahie/index.html

Other sites provide data that can be copied and pasted into a data file.Example-CNN makes it’s poll reports available as

PDF’s but not the raw data

SummaryWhen analyzing data leave no stones

unturned or if that is impossible turn over as many as

possible and acknowledge that you couldn’t turn all of them over.

When interpreting an analysis ask yourself if they have turned over the important stones and or accounted for the ones that they couldn’t turnover.