Psychology

Unit 2: Methods and Statistics

Unit 2 Overview

• RMS 1.1: Describe the scientific method and its role in psychology• RMS 1.2: Describe and compare a variety of quantitative and qualitative

research methods• RMS 2.1: Identify ethical standards psychologist must address regarding

research with human participants.

Unit EQ: How have philosophical perspectives and theoretical approaches shaped the development of psychology?

You will need to be able to “Do” the following:

• Psychologists use several approaches to conducting research, all sociologists follow a seven step research process, and psychologists are bound by ethical guidelines.

You will need to be able to “Understand” the following:

Unit 2 Outline

Concept 1: Conducting Psychological ResearchLesson: 1 2 3

Concept 2: Ethics

Conducting Psychological Research

Vocabulary

• scientific method • Dependent variable • Independent variable • Experimental group

• Control group• Double-blind study • Confounding variable• Placebo

EQ: How do psychologists use a variety of scientific research methods to draw reasonable conclusions?

• RMS 1.1: Describe the scientific method and its role in psychology

• RMS 1.2: Describe and compare a variety of quantitative and qualitative research methods

Activator:

Steps of the Scientific Method

1. Question• Research questions are best

focused on behavior rather than constructs that cannot be seen or measured directly.

2. Hypothesis• Form a hypothesis about the

answer to the research question.• A hypothesis is an educated guess• Specifies a relationship between

two aspects. (i.e. IV & DV)

3. Testing the Hypothesis• A hypothesis cannot be considered

to be correct until it has been scientifically tested and proved to be right..

• May use a variety of research methods to test a hypothesis.

4. Analyzing the Results• What do their findings mean?• Psychologists often look for

patterns and relationships in the data.

5. Drawing Conclusions • Psychologists draw conclusions about their research question and their

hypothesis.• When observations do not support a hypothesis, they often must change the

theories or beliefs from which the hypothesis was derived.

• Psychologists use the experimental method to answer questions about cause and effect.

• The hypothesis specifies the relationship between two aspects. (i.e. the IV and DV)

• Independent Variables (IV) and Dependent Variables (DV)• Experiments have variables, which are factors that can vary, or

change.• The independent variable is the factor that researchers

manipulate.• The dependent variable is the factor whose value depends on

a change made to the independent variable.

Research Design: Hypothesis and Variables

Research Design: Operational Definition

• Specific statements describing how the IV is manipulated and how the DV is measured.

Replication• The ability of an entire experiment or study to be reproduced,

either by the researcher or by someone else working independently.

• It is one of the main principles of the scientific method• Why?

Adderall Experiment Exercise 1

Hypothesis: If a person diagnosed with Attention Deficit Disorder (ADD) is given 20mg of Adderall then his/her focus time will increase.

Assessment Prompt: Using all the hypothesis above, identify the independent variable (IV) and dependent variable (DV). Write your answer on a sheet of paper.

IVDV

Extraneous & Confounding VariablesExtraneous Variables: Undesirable variables that influence the relationship between the variables that an experimenter is examining.

Other Factors(Extraneous & Confounding Variables)

Confounding Variables: Extraneous variables that vary with the levels of the independent variable are the most dangerous type in terms of challenging the validity of experimental results.

Variables

Questions: 1. In the Bystander Effect study or the Adderall Study, what

might be some of the confounding variables?2. What does the phrase “the power of suggestion” mean?

Design an Experiment• Assuming that the “power of suggestion” is the only variable

you are worried about, you are to design an experiment that compensates for this variable.

• The details of your experiment should be written down.

Blind Studies

Double-Blind Studies• Participants and researchers are unaware of who receives the treatment.• Double-blind studies help researchers avoid the influence of expectations

and remain unbiased.

Single-Blind Studies• Participants unaware of the treatment.• Helps to avoid The Placebo Effect

– A placebo is a substance or treatment that has no effect apart from a person’s belief in its effect.

– Feeling better simply because we expect to feel better—and for no other reason—is an example of the placebo effect.

Groups• Experimental and Control

Groups– Members of an

experimental group receive the treatment; members of a control group do not.

– All other conditions are held constant for both the experimental group and the control group.

– A controlled experiment uses both a control group and an experiment group.

Selection of Subjects

Random Sample• The process of choosing

the research participants from the population

• Happen BEFORE assignment

Random Assignment

• Each participant has equal chance of being placed into any group

• Placement into experimental or control group

Samples• Sampling Bias (Selection Bias) is systematic error due to a non-

random sample of a population, causing some members of the population to be less likely to be included than others, resulting in a biased sample.

• Ensure samples accurately represent the population.• Random Assignment & Sample

• individuals are selected by chance from the target population.

• Stratified Sample• consists of subgroups in the population that are represented

proportionally.• A large random sample is more likely to be accurately stratified

even if researchers take no steps to ensure that it is.

Participatory Learning – Flawed Experiment

1. Hypothesis: “Smart” people tend to be more open-minded and flexible.

2. Subjects: To test the hypothesis above, the experimenter asks a wide variety of friends to complete a puzzle that requires flexibility. Then he or she compares their scores.

3. Procedure: The experimenter tries to test the hypothesis above on his friends, but they are too busy. Instead, he or she uses strangers. The experimenter administers a brief intelligence test, then gives subjects a test of flexibility. In the morning he or she finds a group in the cafeteria and passes out the tests to them. In the afternoon, the experimenter finds people in the library who are studying by themselves.

Pick out the flaws in the following statement.

Extraneous Variables

• Placebo Effect • Experimenter Effect (Bias)• Observer Bias• Sampling Bias/Selection Bias/Volunteer Bias• Observer Effect (Hawthorne Effect)• Courtesy Bias

Bias is a predisposition to a certain point of view

Quasi-Experiment (Natural Experiments)• Quasi (Similar or Seemingly)• A quasi-experimental design is one that looks a bit like an

experimental design but lacks the key ingredient -- random assignment.

• Experiments that take advantage of natural occurrences are quasi-experiments• Example 1: comparing achievement level of first-born children

with that of later-born children• Example 2: comparing student performance at two schools, one

of which has a lower student-teacher ratio. • The experimenter is unable to assign subjects to treatment

level - the subjects are already in pre-existing groups.

Adderall Experiment Exercise 2

Hypothesis: If a person diagnosed with Attention Deficit Disorder (ADD) is given 20mg of Adderall then his/her focus time will increase.

Assessment Prompt : Using all terms on the vocabulary sheet, design and label and experiment that tests the above hypothesis

Adderall Experiment Exercise 2Vocabulary Application to the Experiment

Independent Variable

Dependent Variable

Control Group

Experimental Group

Placebo

Single-Blind Study

Double-Blind Study

20mg of Adderall

Groups that receives the Placebo not the Adderall

Group that receives the Adderall

False pill to make up for the power of suggestion

Researcher knows who took the Adderall/Subject Doesn’t

Neither Researcher or Subject knows who took Adderall

Ability to Focus

• The tendency of research subjects to change their behavior as a result of their awareness of being observed.

• It was named for a 1927 workplace study.

The Hawthorne Effect

Case Study: Learning from a Flawed Experiment

• Was not a blind study

• Did not have a control group

• Small Sample Size

• Results of the study may have been misinterpreted

Flaws in the Hawthorne Study

Summarizing Activity

5 Steps of the Scientific Method, 2 Variables, and Questions Remaining

Conducting Psychological Research: Methods and Data

Vocabulary

• Quantitative • Qualitative • Naturalistic Observation• Interviews

• Case Study• Psychological Tests • Longitudinal method• Cross-Sectional Method • Survey Method

EQ: How do psychologists use a variety of scientific research methods to draw reasonable conclusions?

Activator: Remember the Methods of Research

Bystander EffectAnd

Diffusion of Responsibility

KittyGenovese

Assignment: Experiment Creation• Create a testable thesis• Your group should then design an experiment that could be

used to test the phenomenon of diffusion of responsibility (bystander effect).

• Include as many details as possible.• Be prepared to share out.

Psychological Methods

Psychological Methods

Psychological Methods

Volunteer Bias

• When conducting surveys, bias may occur on the part of the respondents.

• Volunteer bias: People who volunteer to participate in studies may have a different outlook from people who do not volunteer.

– Volunteers are usually more willing to disclose personal information.

– They may have more spare time to participate.– Volunteers probably do not represent the target population.

Conducting Psychological Research: Methods and Data

Vocabulary

• Median • Mode • Mean• Correlation coefficient• Central tendency • variability • histogram

• descriptive statistics• Inferential statistics • range • standard deviation (SD)• Statistical significance • normal distribution• sample

Activator:

EQ: How do statistical concepts apply to psychological research?How do ethical and legal guidelines impact psychological research?

Statistics• Statistics: Branch of mathematics concerned with the

collection and interpretation of data from a sample.• Descriptive Statistics: a way of organizing numbers and

summarizing them so that they can be understood.• Two Main Types

• Measure of Central Tendency: Used to summarize the data and give you one score that seems typical

• Measure of Variability: Used to indicate how spread out the data are.

• Inferential Statistics: drawing conclusion by analyzing the data to find differences and meaning in the data

Critical Thinking Activity

Experimental Group

Control Group

Average Score(Mean)

81% 67%

Highest Score 89% 87%Lowest Score 73% 34%Median Score

(Mid-Point)79% 77%

Complete Methods of Psychology: Critical Thinking Activity worksheet in your packet.

Descriptive Statistics

Central Tendency• Mean: “The Average” Most commonly used measure of

central tendency. Add up all the numbers in a set and then divide by the total amount of numbers used.

• Median: Middle number in a set of data(Helps if there are a few extreme scores)

• Mode: Most frequent score• Bimodal: two very different yet very frequent scores. In this

case no measure of central tendency does you much good.

Frequency Distribution

Frequency Distribution: A table or graph that shows how often different numbers, or scores, appear in a particular set of scores.

Polygon Histogram (bar graph) Frequency Table

Measures of Variability• Range: Difference between the highest and lowest score in a

set of scores.

• Is limited as a measure of variability when extreme scores are involved

Measures of Variability• Standard Deviation:

Measures of Variability• Z-score: The way of calculating how many standard deviations

you are away from the mean. Provides a way of comparing sets of data to the normal distribution (such as IQ test scores)

Standard Deviation: IQ

Curve

Inferential Statistics

One method psychologists use to analyze and interpret their observations is correlation. Correlation is a measure of how closely one thing is related to another. The stronger the correlation between two things, the more closely the two things are related.

• Positive correlation occurs when an increase in one thing is accompanied by an increase in the other.

• Negative correlation occurs when a increase in one thing is accompanied by a decrease in the other. (or vice versa)

Positive and Negative Correlation

Analyzing the Observations

• Correlation describes relationships, but it does not reveal cause and effect.

• Just because two things are related does not necessarily mean that one causes the other.

Limits of Correlation

Correlation: Scatterplot

Correlation vs. Causation• What do you think is meant by the statement , “Correlation

does not imply causation.”?

Correlational Coefficient• It represents the direction and strength of the relationshp.• Ranges between +1.0 and -1.0.• The closer r is to +1.0 and -1.0 the stronger the relationship

Assignment: Frankenstein and Ethics

• In your packet, read Ethics in Experimentation: Frankenstein and Complete Questions 1, 3-5

• REMINDER: UNIT 1 Exam is Wednesday STUDY!!!

APA Ethical Guidelines for Human Research

• Informed Consent - participants must know that they are involved in research and give their consent or permission

• Deception - if the participants are deceived in any way about the nature of the study, the deception must not be so extreme as to invalidate the informed consent.

• Coercion - participants cannot be coerced in any way to give consent to be in the study.

• Anonymity-the identities and actions of participants must not be revealed in any way by the researcher.

• Risk-participants cannot be placed at significant mental or physical risk. This clause requires interpretation by the review board.

• Debriefing Procedures -participants must be told of the purpose of the study and provided with ways to contact the researchers about the results.

Unit 1 Exam Topics

• Definition of Psychology• Applied vs. Research Psychologist• Historical Figures/Contributions• Psychological Perspectives• Experimentation (Terms and Application)• Data (Correlation) • Methods of Research• Ethics