Chapter 2Research Methods

It is actually way more exciting than it sounds!!!!

Conducting Research

• 6 step process1. Form a research question

2. Form a hypothesis

3. Test the hypothesis

4. Analyze results

5. Draw conclusions

6. Replicate study

Experimental Method• Formulate Hypothesis• Design Research/Study Method

(type of method: naturalistic observation, case studies, surveys, experiments, etc.)

• Collect the Data• Analyze the Data • Report the Findings (journal,

critique, replicate)• Draw Conclusion or Theory on

Explanation of Findings

Research terms to know

• Hypothesis – testable prediction

• Replication– Repeating the study to ensure outcome is the

same

Types of research methods

• Survey method

• Case Study method

• Naturalistic method

• Correlational method

• Longitudinal method

• Cross-sectional method

• Experimental method (laboratory or field)

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The Survey Method

• A technique for getting self-reported attitudes, opinions or behaviors of people usually done by questioning

• Conduct via interview, mail, phone, or internet

• They are cheap, anonymous, you get a diverse population, and easy to get a random sampling (sample that represents your population you want to study).

Sampling• Identify the

population you want to study.

• The sample must be representative of the population you want to study.

• GET A RANDOM SAMPLE.

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Survey

Random Sampling

If each member of a population has an equal chance of inclusion into a sample, it is called a

random sample (unbiased). If the survey

sample is biased, its results are not valid.

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Survey Method - problems

• Low Response Rate

• People Lie or just misinterpret themselves.

• Wording Effects– Wording can change the results of a

survey

Case Studies

• A detailed picture of one or a few subjects.

• Tells us a great story…but it just describes behavior

• Does not explain why anything is happening .

The ideal case study is John and Kate. Really interesting, but what does it tell us about families in general?

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Case Study

A clinical study is a form of case study in which the therapist

investigates the problems associated

with a client.

http://behavioralhealth.typepad.com

Clinical Study

Naturalistic Observation

• Watch subjects in their natural environment.

• Do not manipulate the environment.

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Correlational Research• Detects relationships between variables.• Does NOT say that one variable causes

another.

There is a positive correlation between ice cream and murder rates. Does that mean that ice cream causes murder?

Types of CorrelationPositive Correlation• The variables go in

the SAME direction.

Negative Correlation• The variables go in

opposite directions.

Studying and grades has a positive correlation.Drug use and grades has a negative correlation

CorrelationPositive Correlation

As one number increases, the other increases.

Ex: Study time to GPA

Negative Correlation

As one number increases, the other decreases.

Ex: Absences to GPA

CORRELATION IS NOT CAUSATION!!!• People that floss everyday live 3 years longer than those that do not.

• Red wine drinkers live longer than those that do not drink red wine.

• As speed limits increased on America’s highways, the death rate went down.

• Women with breast implants commit suicide 3 times as often as those without breast implants.

• Children who are played Mozart in the womb have higher IQ’s.

• Marijuana users in youth are more likely to have mental illness as adults.

• As ice cream sales increased, so did shark attacks.

• More TV’s per person in a country, the longer people live.

Experimental Method• Looking to prove

cause and effect relationships.

• Laboratory v. Field Experiments

Smoking causes health issues.

• Identify the population you want to study.

• The sample must be representative of the population you want to study.

• GET A RANDOM SAMPLE.

Population & Sample

Variables• Independent Variable (I.V.): manipulated by

experimenter

• Dependent Variable (D.V.): MEASURED variable influenced by independent

• Operational definition

• Confounding/extraneous variables

Random Assignment

• Once you have a random sample, randomly assigning them into two groups helps control for confounding variables.

Assign participants to groups

• Experimental group– Receives the

independent variable

• Control Group– Does not receive the

independent variable– May receive a placebo

• A false treatment– Make cause the

placebo effect

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Flaws in Research

• Sampling Bias

• Overgeneralization

• Placebo effect

• Hawthorne/Barnum effect

• Experimenter Bias

Eliminating Experimenter bias

Single-blind study

• Participants do not know what group they are in

Double-blind study

• Participants and experimenters are unaware who receives treatment

APA Ethical Guidelines for Research

• IRB- Institutional Review Board– Must approve your

study 1st

• Both for humans and animals.

Human Research

• No Coercion- must be voluntary

• Informed consent• Confidentiality &

Anonymity• Do not harm• Must debrief after

Animal Research

• Clear purpose• Treated in a

humane way• Acquire animals

legally• Least amount of

suffering possible.

Normal Distribution

68% are within One standard deviation from mean

95% are within Two standard deviations from mean

Bell or Normal Curve

StatisticsDescriptive Statistics

Central Tendency:

mean – average

median – middle score

mode – most reoccurring number or numbers

Measures of Variability:

Standard deviation: shows how spread out the scores are from the mean

Range: distance from smallest score to the largest score

Measures of Central Tendency

A Skewed Distribution

Skews

Other measures of variability

• Range: distance from highest to lowest scores.

• Standard Deviation: the variance of scores around the mean.

• The higher the variance or SD, the more spread out the distribution is.

• Do scientists want a big or small SD?

Shaq and Kobe may both score 30 ppg (same mean).But their SDs are very different.

Standard Deviation