Data Collection

11/27/2012

Readings• Chapter 8 Correlation and Linear Regression (Pollock)

(pp 199- 206)

• Chapter 6 Foundations of Statistical Inference (Pollock) (pp 122-135)

Homework

• Homework Due 11/29• Chapter 8– Question 1: A, B,C,D – Question 2: A, B, C, D, E – Question 3: A, B, C – Question 4: A, B, C, D – Question 5: A, B, C, D, E, G

OPPORTUNITIES TO DISCUSS COURSE CONTENT

Office Hours For the Week

• When• Wednesday 11-1• Thursday 8-12

• And by appointment

Course Learning Objectives

• Students will learn the basics of polling and be able to analyze and explain polling and survey data

• Fourth, students will learn the basics of research design and be able to critically analyze the advantages and disadvantages of different types of design.

OBSERVATION

Observation

• What is it

• Types of Observation

Problems of Observation

• Reactivity

• Ethics

Which Method to use?

THE LITERATURE REVIEW

What it Should Contain

• Bring the reader up to speed on the status of the research (what has been done)

• Establish face validity (why I am using these variables)

• Point out potential problems with previous research

What it should Contain

• what are the main texts in this area

• what are the general theories in this area

• how has the question been measured in the past

Interviewing and Sampling

QUESTIONNAIRE CONSTRUCTION

Question Style

• Open Ended (advantages & disadvantages)

• Closed Ended (advantages & disadvantages)

Demographic Questions

• Who are you?

• These tend to be overrated

• Don’t get too personal!

Behavior Questions

• What do you do, and how often?

• Knowing behavior is a good dependent and independent variable

Opinion and Attitude Questions

• What do you think?

• Easy to Answer

Knowledge/Factual Questions

• Use sparingly

Question Order is Key

• Intro and Filter

• First Questions

• Major Questions

• Final Questions- demographics

How you should Phrase Questions• Language (be clear)

• One question 1 concept

Information Level

BIAS

Interviewer Bias

• You can’t use inflections

• You can’t give hints-

• “Amber, do you think the Bill of Rights is a good thing or a bad thing?” – Krusty the Klown“Um . . .” – Amber Dempsey“Take your time, dear.” – Krusty the Klown“Good thing!” – Amber Dempsey

Respondent Bias

• Socially Acceptable Questions

• Always Remember Homer Simpson's Code of the Schoolyard– Don't tattle – Always make fun of those different from you. – Never say anything, unless you're sure everyone

feels exactly the same way you do.

Question Bias

• Leading Questions

• Honey Boo Boo Redux

• Confusing Questions– Does it seem possible or does

it seem impossible to you that the Nazi extermination of the Jews never happened?

A bad question

• 1. What do you think is the most important issue currently facing St. Edward’s University?a. Grounds keepingb. Landscapingc. Heatingd. Athletic Field Maintenance

Another One

If you had to make up the SEU Budget, and could only keep one of the following activities which of the items would you keep?a. Faculty Travel Budgetb. Expanded Library Hoursc. Reduced parking rates for facultyd. Discounted tickets for Topper Club members

Info Level problem

With the problems of “mad cow” disease and potential problems with the existing BGH growth hormone, do you agree that Texas Taxpayers should stop funding tests using the experimental BVT growth hormone on Texas Livestock

a. Agreeb. Disagree.c. Don't Know

Ensuring Reliability and Validity

• Pre-Test

• Pilot Test

Sampling

After we write the survey, we have to select people!

SAMPLINGThe Source of Public Opinion

What is a population

• The opinions of everyone in your group

• The Census includes 225 Million Adults

• Cost 11.8 billion dollars

• Takes years to compile

What is Sampling?• Sampling is the

technique of selecting a representative part of a population to estimate the total population

The Sample• A sample is considerably smaller than the total

population.

• Samples that are said to mirror the population are said to be representative.

These Numbers Have to be drawn properly… or it is not representative

The Concept of Sampling• Blood Tests

• Food Tests

Collecting a sample

• Population

• Sampling Frame

• The Sample itself

The Practicality of Sampling

• Time

• Money

• Size

The Laws of Sampling

• The Law of Large Numbers• if cost is not a major consideration it is better to collect

data for ones target population than for a sample thereof

• if cost dictates that a sample be drawn, a probability sample is usually preferable to a nonprobability sample.

• all probability samples yield estimates of the target population.

• The accuracy of estimates is expressed in terms of the margin or error and the confidence level.