Presentation on theme: "Chapter 2 Notes Psychological Research Methods and Statistics"— Presentation transcript:
1 Chapter 2 Notes Psychological Research Methods and Statistics PsychologyChapter 2 NotesPsychological Research Methods and Statistics
2 What is Research?Psychologists must first decide how to approach the research issue. Then they conduct the research in one of a variety of ways to test a hypothesis, solve a problem, or confirm previous findingsPre-Research DecisionsBegin by developing a hypothesisLook for evidence/conduct researchResearchers select a sample – a relatively small group out of the total population under studyMust be representative of the populationChoose a purely random sampleUse a stratified sample – subgroups in the population are represented proportionally
3 Methods o f ResearchNaturalistic Observation – observing behaviors with out intruding or disturbing those being observedCase studies are intensive studies of a person or group of peopleLong-term observationsDiariesTestsInterviewsSurveys involve interviews and/or questionnaires. Very practical way to gather data
4 Longitudinal Studies occur when a psychologist studies the same group of people at regular intervals over a period of years to determine whether their behavior and/or feelings have changed and if so, how.Cross-Sectional Studies are when psychologist organize people into groups on the basis of ageThe groups are randomly sampled with simultaneously withSurveysTestsObservations
5 Correlations and explanations Correlations describe how two sets of data relate to each otherExperimentsHypothesis – educated guessVariables – conditions and behaviors that are subject to changeIndependent variable is changed or altered so the experimenters can observe its effectsDependent variable changes in relation to the independent variableExperimental group – those who are exposed to the independent variableControl group – those who are not exposed to the independent variable
6 Ethical IssuesEthics are the methods of conduct or standard for proper and responsible behaviorPlan to minimize possible misleading resultsMaintain the dignity and welfare of the participantsObey all state, federal, and professional laws, regulations, and standardsReach agreements regarding the rights and responsibilities of the participants and the researchersObtain signed, informed consentDeception is used only if no better alternative is available
7 Problems and solutions in research The investigation of psychological issues is a painstaking process. Psychologists must recognize and resolve errors while doing researchSelf-fulfilling ProphecySelf-fulfilling Prophecy involves having expectations about a behavior and then acting in some way, usually unknowingly to carry out that behaviorAvoiding a Self-fulfilling ProphecyDouble-blind experiment – neither the experimenter nor the participants know which participants are receiving the experimental stuffSingle-blind experiment – the participants don’t know if they’ve received the stuff or the placebo, but the experimenter does.
8 The Milgram Experiment Stanley Milgram (1960s)Told people to act like they were receiving electric shocks to see how the person supposedly delivering the shocks would respondMost of those delivering the shocks continued to deliver them through the maximum capacity of electricityConclusion was the people will hurt others when told to do so by an authority figurePlacebo EffectPlacebo effect happens when a person’s illness or physical state changes when they simply think they are receiving treatment
9 Statistical Evaluation Psychologists must collect and evaluate evidence to support their hypothesis.Descriptive StatisticsDescriptive Statistics is the listing and summarizing of data in a practical, efficient way through graphs and averagesFrequency distributions are commonFrequency polygons are like line graphs that compare two sets of dataNormal Curve (aka a bell curve) is where the curve is highest in the middle and tapers off towards both ends. It is symmetrical
10 Measures of Central Tendency Central tendency is a number that describes something about the “average” scoreMode is the most frequent scoreBimodal indicates there are two frequent scores/modesMean is what most people think of as an averageThis is the balance pointMeasures of VarianceMeasures of variance provide an index of how spread out the scores of a distribution areStandard Deviation is a better measure of variance because it uses all the data points in its calculation.
11 Correlation Coefficients describe the direction and strength of the relationship between two sets of observationsPositive correlation means as one variable increases so does the otherNegative correlation means as one variable increases, the other decreasesScatterplots are graphs of scores on the two variablesInferential StatisticsInferential statistics allow researchers to determine whether the data they collect support their hypotheses, or whether their results are merely due to chance outcomesProbability - what is the probability that something will happen?Chance – could the results be due to chance?