Study announcement if you are interested!Study announcement if you are interested!

QuestionsQuestions

Is there one type of mixed design that is more common Is there one type of mixed design that is more common than the other types?than the other types?

Even though there are a lot more participants in a between Even though there are a lot more participants in a between subjects factorial design than within subjects, does this subjects factorial design than within subjects, does this complexity lead researchers to be more apt to using within complexity lead researchers to be more apt to using within subjects rather than between subjects?subjects rather than between subjects?

Is there a maximum number of factors or is it limitless if you Is there a maximum number of factors or is it limitless if you can make a study around them?can make a study around them?

How would you draw 2x2x4 experiment?How would you draw 2x2x4 experiment? If a variable causes increased variance should you make If a variable causes increased variance should you make

that variable a factor?that variable a factor? If you have a 3-factor study do all three lines have to cross If you have a 3-factor study do all three lines have to cross

to indicate an interaction between the factors?to indicate an interaction between the factors?

More QuestionsMore Questions

What is the significance of an interaction in a given What is the significance of an interaction in a given study that uses a factorial design?study that uses a factorial design?

Is it always necessary to use statistics in an Is it always necessary to use statistics in an experiment?experiment?

On the upcoming exam, can you please provide a On the upcoming exam, can you please provide a list of key terms for us to reference so that we can list of key terms for us to reference so that we can focus on understanding their meaning and focus on understanding their meaning and application rather than vocabulary lists?application rather than vocabulary lists?

Is there a way to know our grades before the final?Is there a way to know our grades before the final? For the extra credit paper can it be a critique about For the extra credit paper can it be a critique about

a topic we discussed in class?a topic we discussed in class?

Descriptive and Correlational Descriptive and Correlational Research StrategiesResearch Strategies

Chapters 12 and 13Chapters 12 and 13

Dusana RybarovaDusana RybarovaPsyc 290B Psyc 290B

May 31 2006May 31 2006

Outline:Outline:

1.1. Observational research designObservational research design

2.2. Survey research designSurvey research design

3.3. Case study designCase study design

4.4. Correlational research strategyCorrelational research strategy

IntroductionIntroduction both the descriptive and correlational strategies are both the descriptive and correlational strategies are

nonexperimental approaches to researchnonexperimental approaches to research no attempt to manipulate or control or interfere with the no attempt to manipulate or control or interfere with the

variablesvariables descriptive strategydescriptive strategy

– measures a variable(s) as they exist naturallymeasures a variable(s) as they exist naturally– the goal is to describe the variable(s)the goal is to describe the variable(s)– three descriptive research designsthree descriptive research designs will be considered will be considered

observational research, survey research, case study researchobservational research, survey research, case study research

correlational strategycorrelational strategy– measures two or more variables as they exist naturallymeasures two or more variables as they exist naturally– the goal is to establish that a relationship exists between the goal is to establish that a relationship exists between

variablesvariables

1. Observational research design1. Observational research design

in the observational research design the in the observational research design the researcher observes and systematically records researcher observes and systematically records the behavior of individuals in a order to describe the behavior of individuals in a order to describe the behaviorthe behavior

naturalistic observationnaturalistic observation– a researcher observes behavior in a natural setting as a researcher observes behavior in a natural setting as

unobtrusively as possibleunobtrusively as possible– e.g. observing the behavior of children in a classroome.g. observing the behavior of children in a classroom– (+) behavior is observed in the real world(+) behavior is observed in the real world– (-) time consuming, potential for observer influence(-) time consuming, potential for observer influence

1. Observational research design1. Observational research design participant observationparticipant observation

– the researcher engages in the same activities the researcher engages in the same activities as the people being observed, in order to as the people being observed, in order to observe and record their behaviorobserve and record their behavior

– e.g. gang meeting or treatment of mental e.g. gang meeting or treatment of mental patientspatients

– (+) get info not accessible otherwise(+) get info not accessible otherwise– (-) time consuming, can be dangerous(-) time consuming, can be dangerous

1. Observational research design1. Observational research design

contrived observationcontrived observation– observation of behavior in settings arranged observation of behavior in settings arranged

specifically for observing and recording of specifically for observing and recording of behaviorbehavior

– e.g. parent-child interactionse.g. parent-child interactions– (+) don’t have to wait for the behavior to occur(+) don’t have to wait for the behavior to occur– (-) less natural(-) less natural

2. Survey research designs2. Survey research designs

a research study that uses a survey to obtain a a research study that uses a survey to obtain a description of a particular group of individuals is description of a particular group of individuals is called a survey research design (only describing)called a survey research design (only describing)

e.g. customer surveys, eating behavior surveys e.g. customer surveys, eating behavior surveys etc.etc.

constructing a surveyconstructing a survey– e.g. demographic questions at the end of survey, e.g. demographic questions at the end of survey,

sensitive questions in the middle of the survey, sensitive questions in the middle of the survey, appropriate vocabularyappropriate vocabulary

2. Survey research designs2. Survey research designs

three types of questions:three types of questions: open-ended questionsopen-ended questions

– e.g. What do you think about environmental pollution?e.g. What do you think about environmental pollution?– advantages (flexibility)advantages (flexibility)– limits (different interpretations of questions, different limits (different interpretations of questions, different

format and length of answers, difficult to quantify)format and length of answers, difficult to quantify)

restricted questionsrestricted questions– you present the participant with a limited number of you present the participant with a limited number of

response alternatives (e.g. multiple choice questions)response alternatives (e.g. multiple choice questions)– advantages (easy to quantify and analyze)advantages (easy to quantify and analyze)– limits (less flexible than open-ended questions)limits (less flexible than open-ended questions)

2. Survey research designs2. Survey research designs

Self-report measures (cont.)Self-report measures (cont.)– types of questions (cont.)types of questions (cont.)

rating scale questionsrating scale questions– require a participant to respond by selecting a numerical require a participant to respond by selecting a numerical

value on a predetermined scalevalue on a predetermined scale– participants have the tendency to avoid the two extreme participants have the tendency to avoid the two extreme

categories (actual scale is reduced by 2 categories)categories (actual scale is reduced by 2 categories)– participants tend to answer all of the questions in the same participants tend to answer all of the questions in the same

way (this is called response set)way (this is called response set)– semantic differential (presents a list of adjectives, e.g. semantic differential (presents a list of adjectives, e.g.

honest, and asks participants to use the scale to rate how honest, and asks participants to use the scale to rate how well each adjective describes a particular individual (not well each adjective describes a particular individual (not descriptive descriptive describes perfectly))describes perfectly))

2. Survey research designs2. Survey research designs

selecting relevant and representative participantsselecting relevant and representative participants– e.g. specific groupse.g. specific groups

administering a surveyadministering a survey– mail surveysmail surveys

convenient and nonthreatening but response rates are lowconvenient and nonthreatening but response rates are low

– phone surveysphone surveys can be conducted from home but time consumingcan be conducted from home but time consuming

– in-person surveysin-person surveys 100% response rate but time consuming with individual 100% response rate but time consuming with individual

interviewsinterviews

3. Case study design3. Case study design

involves the in-depth study and detailed involves the in-depth study and detailed description of a single individual description of a single individual

may involve an intervention or treatment may involve an intervention or treatment administered by the researcheradministered by the researcher

when a study does not include any treatment or when a study does not include any treatment or intervention, it is often called a case historyintervention, it is often called a case history

e.g. Eve White (multiple personality disorder) or e.g. Eve White (multiple personality disorder) or neuropsychological patients (H.M.)neuropsychological patients (H.M.)

3. Case study design3. Case study design

strengthsstrengths– not averaged over a diverse groupnot averaged over a diverse group– detailed descriptiondetailed description– vivid, convincingvivid, convincing– can study rare and unusual eventscan study rare and unusual events– can identify exceptions to the rulecan identify exceptions to the rule

weaknessesweaknesses– limited generalizationslimited generalizations– potential for selective biaspotential for selective bias– potential for subjective interpretationspotential for subjective interpretations

4. Correlational research strategy4. Correlational research strategy

two variables are measured and recorded for each two variables are measured and recorded for each individual individual

the measurements are then reviewed to identify the measurements are then reviewed to identify any patterns of relationship that exist between the any patterns of relationship that exist between the two variables and to measure the strength of the two variables and to measure the strength of the relationshiprelationship

can be used for making predictionscan be used for making predictions– first variable is called predictor variable (e.g. GRE first variable is called predictor variable (e.g. GRE

score)score)– second variable is called criterion variable (e.g. second variable is called criterion variable (e.g.

academic performance)academic performance)

4. Correlational research strategy4. Correlational research strategy

Positive relationshipPositive relationship– There is a tendency for two variables to change There is a tendency for two variables to change

in the same direction; as one variable in the same direction; as one variable increases, the other also tends to increase.increases, the other also tends to increase.

Negative relationshipNegative relationship– There is a tendency for two variables to change There is a tendency for two variables to change

in opposite directions; increases in one variable in opposite directions; increases in one variable tend to be accompanied by decreases in the tend to be accompanied by decreases in the other.other.

4. Correlational research strategy4. Correlational research strategy

positive correlation

0

510

1520

2530

3540

45

1 2 3 4 5 6 7 8

positivecorrelation

negative correlation

0

510

1520

2530

3540

45

1 2 3 4 5 6 7 8

negativecorrelation

4. Correlational research strategy4. Correlational research strategy

Applications of the correlational strategyApplications of the correlational strategy– Prediction Prediction

Predictor variable (e.g. GPA)Predictor variable (e.g. GPA) Criterion variable to be predicted (e.g. grad school Criterion variable to be predicted (e.g. grad school

success)success)

– Reliability and validityReliability and validity Calculating correlations in test-retest reliability and Calculating correlations in test-retest reliability and

concurrent validityconcurrent validity

– Evaluating theoriesEvaluating theories E.g. Heredity and IQ correlations between twinsE.g. Heredity and IQ correlations between twins

4. Correlational research strategy4. Correlational research strategy

strengthsstrengths– nonintrusive – natural behaviorsnonintrusive – natural behaviors– high external validityhigh external validity

weaknessesweaknesses– cannot assess causality (e.g. TV and cannot assess causality (e.g. TV and

aggressive behavior)aggressive behavior)– third-variable problemthird-variable problem– directionality problemdirectionality problem– low internal validitylow internal validity