Lecture 2 – What is Statistics? January 17, 2020 Prof. Dan Tortorice Economics 249 – Statistics College of the Holy Cross I am sure you have listened to or read news articles where reporters make statements such as: • The economy expanded by 2% in the last quarter ... • Women make 79 cents for every dollar men make ... • Since 1993, the US firearm homicide rate was cut in half ... Have you ever wondered: • How people know these things? • How did we come up with these numbers? • How can we determine the causes of these fact? If you find these questions interesting then taking a statistics course is the right thing to do. 1 1 Statistics Illustrations • Monty Hall Problem • Birthday Problem • Wald problem • Simpson’s paradox • Going for it on 4th down • Sitting a player in foul trouble. • Flip Coin • Cancer Clusters 2 Data Statistics is the formal analysis of data: • Definition: Data: Quantitative observations. Though data need not be quantitative, in statistics that is what we work with so I will include that in the definition. Data is plural, from Latin datum “something given”. So we say the, at first awkward, data are available, etc. 2.1 Components of Data • Dataset • Raw Data • Variable • Observation • Unit of observation • Element 2 2.2 Types of Data • Time series vs. Cross Section • Quantitative vs. Qualitative • Discrete vs. Continuous • Categorical – Data which can be divided into groups. 2.3 Data Sources • Collect your own. • Outside sources. – FRED (Federal Reserve Economics Database). Macroeconomic Data – Google Finance (Stock Return Data) – Bureau of Labor Statistics – Bureau of Justice Statistics 3
