© 2011 The McGraw-Hill Companies, Inc. Chapter 2 Psychology’s Scientific Method © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Chapter Preview Psychology’s Scientific Method Types of Psychological Research Research Samples and Settings Analyzing and Interpreting Data Conducting Ethical Research Thinking Critically About Research Scientific Method and Health and Wellness © 2011 The McGraw-Hill Companies, Inc.

Scientific Method Science is a method. It’s not what you study, but how you study it. © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Scientific Method observe some phenomenon formulate hypothesis and predictions test through empirical research draw conclusions evaluate the theory IM: Activity Handout 2.1: What is the Operational Definition? © 2011 The McGraw-Hill Companies, Inc.

Scientific Method: Observe Step 1 Observe some phenomenon curiosity variables theory © 2011 The McGraw-Hill Companies, Inc.

Scientific Method: Hypothesize Step 2 Formulate hypotheses and predictions testable prediction derived from theory © 2011 The McGraw-Hill Companies, Inc.

Scientific Method: Research Step 3 Test through empirical research operational definition of variables analyze data using statistical procedures © 2011 The McGraw-Hill Companies, Inc.

Scientific Method: Conclusions Step 4 Draw conclusions replication of results → reliability © 2011 The McGraw-Hill Companies, Inc.

Scientific Method: Evaluate Step 5 Evaluate the theory change the theory? peer review and publication meta-analysis © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Descriptive Research Goal: Describing a phenomenon observation surveys and interviews case studies © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Descriptive Research Descriptive research does not answer questions about how and why things are the way they are. © 2011 The McGraw-Hill Companies, Inc. 11

Correlational Research Goal: Identify relationships correlation coefficient: r -1.00 ≤ r ≤ 1.00 strength of relationship: magnitude direction of relationship: + / - © 2011 The McGraw-Hill Companies, Inc.

Correlation Coefficients © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Scatter Plots © 2011 The McGraw-Hill Companies, Inc.

Correlational Research Positive Correlations factors vary in same direction ↑ and ↑ … or … ↓ and ↓ Negative Correlations factors vary in opposite direction ↑ and ↓ … or … ↑ and ↓ © 2011 The McGraw-Hill Companies, Inc.

Correlation and Causation correlation does not equal causation third variable problem longitudinal design © 2011 The McGraw-Hill Companies, Inc.

Experimental Research Goal: Determine causation random assignment independent variable(s) – manipulation dependent variable(s) – measurement © 2011 The McGraw-Hill Companies, Inc.

Experimental Research Experimental Group independent variable is manipulated Control Group treated equally, except no manipulation of independent variable © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Validity External Validity representative of real world issues? do results generalize to the real world? Internal Validity are dependent variable changes the result of independent variable manipulation? bias? logical errors? © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Bias and Expectations experimenter bias demand characteristics research participant bias placebo effect double-blind experiment © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Research Sample Population entire group about whom conclusion drawn Sample portion of population actually observed Representative Sample characteristics similar to population opposite of “biased sample” Random Sample equal chance of being selected © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Research Settings “Artificial” world – laboratory setting controlled setting Real world - natural setting naturalistic observation What are the advantages and disadvantages of each setting? © 2011 The McGraw-Hill Companies, Inc.

Analyzing and Interpreting Data Statistics mathematical methods used to report data Descriptive Statistics describe and summarize data Inferential Statistics draw conclusions about data © 2011 The McGraw-Hill Companies, Inc. 23

Descriptive Statistics Measures of Central Tendency mean median mode Measures of Dispersion range standard deviation © 2011 The McGraw-Hill Companies, Inc.

Inferential Statistics does data confirm the hypothesis? statistical significance α = 0.05 (confidence level) bridge between sample and population © 2011 The McGraw-Hill Companies, Inc.

© 2011 The McGraw-Hill Companies, Inc. Research Ethics research participants have rights Institutional Review Board (IRB) APA Guidelines informed consent confidentiality debriefing deception © 2011 The McGraw-Hill Companies, Inc.

Animal Research in Psychology animal research has benefited humans used by 5% of researchers rats and mice used 90% of time standards of care in animal research housing feeding psychological and physical well being © 2011 The McGraw-Hill Companies, Inc.

A Wise Consumer…is skeptical yet open-minded! Cautions exercise caution in applying group trends to individual experience avoid overgeneralizing results look for converging evidence question causal inferences consider the source © 2011 The McGraw-Hill Companies, Inc.