Cheat Sheet for Statistics 101, Cheat Sheet of Statistics

Download Cheat Sheet for Statistics 101 and more Cheat Sheet Statistics in PDF only on Docsity! Cheat Sheet for Statistics 101 Why is having some background in statistics important? “In many cases, judges review the statistical analysis produced by consultants, as presented and critiqued by competing expert witnesses on behalf of the parties at trial. The legal system in general, and judges in particular, become the audience for local government data gathering and analysis.” “Documenting Disparity in Minority Contracting: Legal Requirements and Recommendations for Policy-Makers” Public Administration Review, 2007 What are statistics? Simply information, or data, of any kind, but usually in the form of numbers. How are they used? In three ways: Descriptive statistics: To describe someone or something. Context. Inferential statistics: To find patterns, usually in an effort to find (infer) a relationship between two things How are statistics abused? To only present part of a picture – they part the presenter wants you to see. Or to imply a relationship between two things when the pattern is weak, or, even if the pattern is strong, to imply that a relationship actually matters in the context of all the information – in the big picture. What are some of the most common statistical terms I’ll see? What does a typical person/place/thing look like? Mean average Median middle observation Is the people/places/things pretty similar or is there a lot of variation? Range lowest to highest value Standard deviation how spread out the data are Does X track with Y? Is X related to Y? Does X influence Y? Does X cause Y? Correlation where two sets of data move together – e.g. as one goes up, the other goes up Causation where data indicate that one thing causes or has an influence on another thing Significance Statistical significance when a pattern in the data is so clear it is not likely to be random. It is very likely that something is going on, that something is influencing the data to follow that pattern. Material significance whether or not the pattern, even if crystal clear, matters in the big picture.