Why Statistics? meaningful questions - systematic methods.

Why Statistics?Why Statistics? meaningful questions - meaningful questions - systematic methodssystematic methods

General OverviewGeneral Overview

“ “In most mathematics In most mathematics courses, the problem is courses, the problem is solved when you obtain the solved when you obtain the numerical answer. In numerical answer. In statistics, the problem is just statistics, the problem is just beginning.” beginning.” – Daren StarnesDaren Starnes


“ “Statistics is about data. Statistics is about data. Data are numbers, but they Data are numbers, but they are not just numbers. Data are not just numbers. Data are numbers with a context.” are numbers with a context.” – YMS, p. xiiYMS, p. xii


“ “All models are wrong. All models are wrong. Some models are useful.” Some models are useful.” – George E.P. BoxGeorge E.P. Box

“ “There are three kinds of There are three kinds of lies: lies, damned lies, and lies: lies, damned lies, and statistics.” statistics.” – Benjamin DisraeliBenjamin Disraeli


“ “53.8% of all statistics are 53.8% of all statistics are made up.” made up.” – The back of a package of wipes from HootersThe back of a package of wipes from Hooters


“ “An anonymous sage once An anonymous sage once defined a statistician as “one defined a statistician as “one who collects data and draws who collects data and draws confusions.”confusions.”– CCMC, p. 1CCMC, p. 1

Statistics vs. Other Math Statistics vs. Other Math CoursesCourses

“ “The formation of a statistics The formation of a statistics question requires an question requires an understanding of the difference understanding of the difference between a question that between a question that anticipates a deterministic answer anticipates a deterministic answer and a question that anticipates an and a question that anticipates an answer based on data that vary.” answer based on data that vary.” – ASA, 2005ASA, 2005

Statistics vs. Other Math Statistics vs. Other Math CoursesCourses ContextContext VariabilityVariability EstimationEstimation Research DesignResearch Design Data CollectionData Collection InterpretationInterpretation WritingWriting


ContextContext VariabilityVariability EstimationEstimation

Research Design / Data CollectionResearch Design / Data Collection WritingWriting


How fast is this car going?How fast is this car going?– Leads to a single discreet answer – Leads to a single discreet answer –

Mathematical ThinkingMathematical Thinking

How fast are cars going on I-85 How fast are cars going on I-85 between between I-77 and Concord Mills?I-77 and Concord Mills?– Involves Context, Variability, Estimation, Involves Context, Variability, Estimation,

Research Design, and Writing – Statistical Research Design, and Writing – Statistical ThinkingThinking

Why Statistics?Why Statistics?

Some understanding of statistics Some understanding of statistics helps all educational leaders in helps all educational leaders in the current policy climate. the current policy climate. – Program evaluationProgram evaluation– Emphasis on test scoresEmphasis on test scores– NCLBNCLB– Becoming a reflective practitionerBecoming a reflective practitioner– Becoming a researcher / practitionerBecoming a researcher / practitioner

How Does Statistics Work?How Does Statistics Work?

The PopulationThe Population– The group about which you wish to The group about which you wish to

make conclusions or generalizationsmake conclusions or generalizations– Defined by specific characteristicsDefined by specific characteristics

For our example dataset this For our example dataset this semestersemester– All public school elementary teachers in All public school elementary teachers in

the U.S. during the 1999-2000 school the U.S. during the 1999-2000 school yearyear


The Sampling FrameThe Sampling Frame– The best available list of the members of The best available list of the members of

the populationthe population– Should be as close actual population as Should be as close actual population as

possiblepossible

For our example dataset this semesterFor our example dataset this semester– The list of all public schools in the U.S. The list of all public schools in the U.S.

according to the Common Core of Data from according to the Common Core of Data from the National Center for Education Statistics the National Center for Education Statistics (NCES)(NCES)


The SampleThe Sample– The group of participants you obtain for The group of participants you obtain for

your studyyour study– Should be representative of the populationShould be representative of the population

For our example dataset this semesterFor our example dataset this semester– The participants in the Schools and Staffing The participants in the Schools and Staffing

Survey, 1999-2000 cohortSurvey, 1999-2000 cohort– Public school teacher questionnaire, full Public school teacher questionnaire, full

time onlytime only


Sample Who falls in here?

Sampling Frame

Who falls in here?

Population

How Does Statistics Work?How Does Statistics Work? ParametersParameters

– Quantitative indexes that describe Quantitative indexes that describe characteristics of the populationcharacteristics of the population

– The population “true scores”, what we The population “true scores”, what we would get if we collected data from the would get if we collected data from the entire population, the result of conducting entire population, the result of conducting a censusa census

StatisticsStatistics– Quantitative indexes that describe Quantitative indexes that describe

characteristics of the samplecharacteristics of the sample– The sample values that become our best The sample values that become our best

guesses, or estimates, of population “true guesses, or estimates, of population “true scores”, called parametersscores”, called parameters

Develop the Research Questions

Define the Population to be Studied

Design the Study / Select Methods

Develop a Sampling Plan

Collect Data from the Sample

Calculate Statistics

Use Statistics to Estimate Parameters

Draw Conclusions in Context

Statistical ReasoningStatistical Reasoning

This course is about learning to This course is about learning to use statistical reasoning to help use statistical reasoning to help offer some types of evidence as offer some types of evidence as parts of the answers to questions parts of the answers to questions about educational policy:about educational policy:– Test theoriesTest theories– Evaluate educational interventions / Evaluate educational interventions /

strategiesstrategies– Answer meaningful educational Answer meaningful educational

questionsquestions

The CurriculumThe Curriculum

Descriptive Statistics / Descriptive Statistics / Exploratory Exploratory Data Data AnalysisAnalysis

Correlation / RegressionCorrelation / Regression ProbabilityProbability Inferential StatisticsInferential Statistics

– MeansMeans– Proportions / PercentagesProportions / Percentages

Getting StartedGetting Started

USA Today polls exampleUSA Today polls exampleElectoral Vote tracker siteElectoral Vote tracker siteGallup PollsGallup PollsThe course website The course website

Course OverviewCourse Overview

There is more than one way There is more than one way to unravel a statistics to unravel a statistics problem.problem.

Connections with most Connections with most disciplines abound in disciplines abound in statistics.statistics.

Course OverviewCourse Overview

Make your midterm, final, Make your midterm, final, and class presentation count and class presentation count for you. Find a dataset that for you. Find a dataset that has utility and meaning for has utility and meaning for you.you.

Why Statistics? meaningful questions - systematic methods.

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