Stat 512 – Statistical Methods

What you will learn in this class Evaluate information from research study  What do the results really say?  What don’t they say? Present results effectively  How do we most effectively present the information?  How do we identify patterns and trends? Methods for collecting the data “correctly”  What type of conclusions can we draw?

Materials Statistical Methods for the Social Sciences Investigating Statistical Concepts, Applications, and Methods  Supplied by instructor Access to internet, address Access to Minitab (v 14), Excel, Word Scientific calculator Flash drive or PC-formatted CD Large 3-ring binder

What you will be asked to do in this class Juggle two textbooks… Practice problems and other tasks between classes Weekly homework problems Occasional computer lab assignments 1 group term project One midterm Comprehensive final

What you will be asked to do in this class Participate during class discussions Ask questions of myself and each other Interpret, justify, explain, communicate Use mathematics and computer as tools for analyzing data

What you will not be asked to do Memorize formulas Manipulate equations without understanding where they came from, what they mean, or why they are used Repeat back what I say to you

Investigation 1: Popcorn Production and Lung Disease “Clinical Bronchiolitis Obliterans in Workers at a Microwave-Popcorn Plant”  Kreiss, Gomaa, Kullman, Fedan, Simoes, Enright  New England Journal of Medicine, August 2002

Assessment of Exposure Diacetyl, the predominant ketone in artificial butter flavoring  a marker of organic-chemic exposure Tested air samples and dust samples from various areas in the plant  Plain-popcorn packaging line, bag-printing areas, warehouse, offices, outside  Quality control or maintenance  Microwave-popcorn packaging lines  Mixing room

Data Analysis Low exposureHigh exposure Airway615 Obstruction

Data Analysis Low exposureHigh exposure Airway615 Obstruction Total5858

Data Analysis Low exposureHigh exposure Airway615 Obstruction No 5243 Obstruction Total5858

Vocabulary Variable = characteristic that varies from observational unit to observational unit (the people are objects that you are measuring) Types of variables  Quantitative = measure numeric outcome  Categorical/Qualitative= place into groups Explanatory and Response variables  Explanatory  Response Distribution  The pattern of the results

Investigation 2: Smoking and Lung Cancer Are people with bronchogenic carcinoma more like to be smokers than people with other hospital patients?  Interviewed 605 males with same form  Interviewed 1332 males without lung cancer = “control group”  Classified their level of smoking

Investigation 2: Smoking and Lung Cancer Identify the observational units and variables  Type of variables?  Response vs. explanatory? Create segmented bar graph in Excel  lungcancer.xls Convincing evidence?  Why compared age and economic status?  Why only men?  44% of hospitalized males have lung cancer?

Terminology A sample is the collection of observational units on which the variables have been measured. The population is the total collection of observational units that we are interested in

Summary Using Statistical Methods  Design: Planning and carrying out research studies  Description: Summarizing and exploring data  Inference: Making predictions or generalizing about phenomena represented by the data Important lesson: Type of study determines which conclusions we can draw and which calculations are meaningful…

Before next class Go to Blackboard page > Assignments  Stat 512 Questionnaire  Practice Problems PP 1 (9/22) Submit within Blackboard or me at least one hour prior to start of class… Reading in text  Ch. 1, p , (HW 1 due noon, Friday)