1Statistics is the art and science of designing studies and ana-lyzing the data that those studies produce. Its ultimate goal istranslating data into knowledge and understanding of the worldaround us. In short, statistics is the art and science of learn-ing from data.2Design: Planning how to obtain data to answer the questionsof interest.Description: Summarizing the data that are obtained.Inference: Making decisions and predictions based on the data.3Probability4Sample and PopulationsThe population is the set of subjects in which we are interested.The sample is the subset of the population for whom we have(or plan to have) data.Examples:• General Social Survey (GSS): sample 2765, population alladult Americans (>200 million)• California exit poll: sample 3160, population all CA voters(≈8 million)A census is a complete enumeration.5Descriptive and Inferential StatisticsDescriptive statistics refers to methods for summarizing thedata. The summaries usually consist of graphs and numberssuch as averages and percentages.Interential statistics refers to methods for making predictionsor decisions about a population, based on data obtained from asample of that population.Example — confidence intervals. Of 834 people in a survey,54.0% say they favor handgun control. Using statistical meth-ods, we deduce there is 95% confidence that the true proportionis between 50.6% and 57.4%.6Parameters and StatisticsA parameter is a numerical summary of the population.A statistic is a numerical summary of a sample taken from thepopulation.7Computers and Statistics• Calculators• Minitab•
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