or items of information; these will be numbers in context What is Statistics? Data: Individual facts or items of information; these will be numbers in context Statistics: the science (and art) of learning from data; the mathematics of collecting and analyzing data to draw conclusions and make predictions. A solid understanding of statistics allows people to make sound decisions

Members of a sample are called individuals (people, animals, objects…) When gathering/producing data, there are special considerations: Population: The large group that is being studied Sample: A subgroup from which the data will actually be collected Members of a sample are called individuals (people, animals, objects…) Any characteristic of the individual is called a variable (age, height, favorite color)

Must have GOOD DATA: Available data: already existing data Observational Study: observe the individuals of the sample and measure variables of interest without influencing responses Example: Survey Experiment: an action is performed on the individuals of the sample and the responses to that action are recorded

Extra Credit In 1976, Shere Hite published The Hite Report on Female Sexuality, Seven Stories Press, New York, NY, 2004. The conclusions reported in her book were based upon 3000 returned surveys from approximately 10,000 surveys distributed by various women’s groups. The results were that women are highly critical of men. In what way might the author’s findings be considered flawed (and biased)?

Who are the individuals described by the data? What are the variables? When looking at a study you should be able to answer these questions: Who are the individuals described by the data? What are the variables? Why were the data gathered? When, where, how and by whom were the data produced?

Types of Variables Categorical Quantitative Each piece of data is sorted in groups This data is often verbal responses Quantitative Each piece of data is given a numerical value where mathematical operations are possible

This is often done graphically Once data is gathered/produced, you can investigate how the values of the variable are distributed (how often each value occurs and how the values are spread apart) This is often done graphically Graphs like these help us UNDERSTAND the data, these are not the ending result of analyzing the data

See the scenario on pages 17 – 18 (Airline flights) When given multiple set of data, comparisons often help understand relationships between the data. Converting values to percents may help with comparisons and analysis Ultimately, look for cause and effect relationships Sometimes relationships are influenced by other variables of which you are not aware See the scenario on pages 17 – 18 (Airline flights)

Extra Credit Based upon the information on pages 21 – 25, it is not possible to be totally certain that a conclusion is correct. How do statisticians validate their conclusions are reasonably correct?

“What do the data tell me?” Probability: the chances a particular event will occur; what happens in the long run This is used to predict long term patterns in data and allows you to draw conclusions based upon the likelihood of a particular event. Drawing conclusions is not an exact science. Therefore, we predict results using degrees of confidence (also called confidence intervals) Always ask: “What do the data tell me?”