Variables and Hypotheses

8/29/2013

Readings

• Chapter 1 The Measurement of Concepts (14-23) (Pollock)

• Chapter 2 Measuring and Describing Variables (Pollock) (pp.28-31)

Backing Up Your Data

• Save the Information from the CD onto another media– Flash Drive

– Edshare

• These are just data files, not aprogram

We Will Use the Full Version

Make Sure you move these files

The Files that We Will use• Data Files on the Pollack CD

• GSS2008.SAV- the 2008 General Social Survey Dataset– n=2023 – 301 variables

• NES2008.SAV- the National Election Study from 2008. n=2323 – 302 variables

• STATES.SAV- aggregate level data for the 50 States. N=50 – 82 Variables

• WORLD.SAV- aggregate level data for the nations of the world. n=191 – 69 Variables

OPPORTUNITIES TO DISCUSS COURSE CONTENT

Office Hours For the Week

• When– Friday 10-12– Tuesday 8-12– And by appointment

• Last day to change any class is friday

Course Learning Objectives

1. Students will learn the research methods commonly used in behavioral sciences and will be able to interpret and explain empirical data.

2. Students will learn the basics of research design and be able to critically analyze the advantages and disadvantages of different types of design.

CONCEPTSThe First Steps in Measurement

Concepts

• The words we use to describe political and social phenomenon

• Conceptual Definition- States the concept in unambiguous terms

• The Operational Definition- setting your concept in a way that can be measured

THE SECOND STEP: VARIABLESMeasurement

What are Variables

• These are simply measured concepts

• Giving a concept value is called operationalization

• Good variables take on all values of a concept

• Why variables are important

How We Operationalize Fancy

• Fancy canned tomatoes must have a drained weight not less than 66% of the capacity of the container

• U.S. Grade B or U.S. Extra Standard must have a drained weight of not less than 58% of the capacity of the container

Variable Measurement

• constants

• Dichotomous Variables

• The rest

Dichotomous Variables

The Dependent Variable

• The variable in a relationship you want to explain. The Y variable

• There is only one of these in a relationship

• It changes in response to an independent variable

The Independent variable

• Variables that that cause change in the dependent variable

• The (X) variable

• You may have more than 1 of these

The Relationship Between them

Telling the Difference between I.V.’s and the D.V.

Additive Relationships

• Explaining a Dependent variable with more than 1 independent variable is called an additive relationship!

• Most Social Science relationships involve many i.v.’s…. Why?

Causes of Cancer

Additive Relationships

Independent Variables at Play

Why the Decline?

Antecedent and Intervening Variables

Antecedent• Come before the

independent variable

• Things like Demographics

Intervening• Come in-between the IV

and the DV

• Temporal events

How they can influence relationships

A Spurious Relationship• What antecedent variable might be at play?

Intervening Variable

UNITS OF ANALYSISHow we measure our Variables

Units of analysis

• The unit about which information is collected and that provides the basis of analysis

• Each member of a population is an element

• Why they are important?

Individual Unit

• Studying an individual case or example

• A single survey response

• People, congressmen, presidents, etc

Aggregate Data

• A collection of individual level units

• Often measured in percentages

Counts can distort

The Poor over Time

Immigration over time

Health Care Access

FALLACIES MADE WITH DATA

Ecological Fallacy

• this arises when an aggregate/ecological level phenomenon is used to make inferences at the individual level.

• Taking statewide data and applying to individuals

• Does everyone in MS go to church?

An Example

• On Mr. Burns Wanting to bowl: "Call this an unfair generalization if you must, but old people are no good at everything." Moe the Bartender from the Simpsons

The Exception Fallacy

• taking one person's behavior, attributes, etc and applying it to an entire group

• Using 1 example to define group behavior

Perceptions in Europe

Examples from Texas Style

How We View Others

HYPOTHESES

What Is a Hypothesis

• An educated Guess

• These are explicit Statements

• They Try to explain a relationship

• But they are only tentative until tested

The Null Hypothesis

• The Statement of No Relationship

• What we want to disprove

• The Basic start of research

H0

On Stating the Null “there is no relationship between the

independent and dependent variable”

Correlative Hypothesis

• “there is a relationship between x and y”

• A very weak statement

Positive Hypothesis

• A directional hypothesis

• “as the independent variable increases, the dependent variable increases”

Positive Relationship

On Stating a Positive relationship: There is a positive relationship

between my independent variable (how much I drank) and dependent

variable (the better you look)

Negative Relationship/Hypothesis

• “As the independent variable increases, the dependent variable decreases”

• Also called an inverse hypothesis

Minimum Wage

On Stating a negative hypothesis: There is a negative (inverse) relationship between “beers

drank” (independent) and “grade” (dependent variable)