Chapter 2 Jen Metz

How do psychologists research? Psychologists collect information somewhat like most people do in everyday life-only more carefully and more systematically. 1. Researchers begin a study by asking a specific question about a limited topic or hypothesis 2. Look for evidence- method depends on research topic 3. Pick a sample A. Representative 1. Random sample 2. Stratified sample B. Nonrepresentative

Methods of Research 1) naturalistic observation- how do people act when they know their not being observed? Must avoid disturbing the people or animals-could observe a performance produced by researcher’s presence.naturalistic observation 2) case studies-intensive study of a person or group. Jean Piaget. Does not prove or disprove anything- results can not be generalizedcase studies

Methods of Research continued… 3) surveys-gather data in large groups-use questionnaires or interviews 4) longitudinal studies- a psychologist studies that same group of people at regular intervals over a period of years.longitudinal studies 5) cross-sectional studies-organize groups based on age. Less expensive than longitudinal surveys.

Methods of Research continued… 6) Experiments- allow researchers to control situation and to decrease the possibility that unnoticed, outside variables will influence the results.

1) hypothesis 2) determine variables-independent or dependent 3) experiment testing- experimental or control group 4) measure behavior or experimental and control group 5) compare measurements 6) draw conclusion

Section 2 What is the self-fulfilling prophecy? Having expectations about a behavior and then acting in some way, usually unknowingly, to carry out that behavior. Psychologists must try not to unwittingly influence results- nod, raise of eyebrow Single blind experiment Double blind experiment Milgram experiment Placebo effect

Section 3 Statistics- a branch of mathematics that enables researchers to organize and evaluate the data they collect. Use descriptive statistics to list and summarize data in a practical and efficient way- use graphs Frequency Distribution

Correlations Examine relationship between two sets of observations PositiveNegative

Frequency Polygon/Curve

Normal/Bell Curve

How do you summarize your findings? Use Measure of Central Tendency- describes something about the average score of a distribution Mode- most common score Median- middle score Mean- average

Distributions can be spread out- Measures of Variability- provide an index of how spread out they are. 1) Range- subtract the lowest score in the data set from the highest score and add one. 2) standard deviation- better measure of variability because it uses all the data points in its calculation. Deviation is an average distance of every score to the mean of the scores. Scores above the mean are a positive deviation, scores below the mean are a negative deviation. Deviations are large is scores are spread out. If the distribution of scores are bunched up- deviations tend to be small.