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Lesson Plan – week of November 8, 2010 Monday: – no class (speaker) Tuesday: Review: importance of research and developing a research question, hypothesis Discuss: • Steps – Identify questions of interest – Formulating an explanation – • Theory: broad explanation • Hypothesis: prediction stated in a way that it can be tested Carrying out research designed to support or refute Who participates in the study? Representative sample How do psychologists study behavior? • • Descriptive studies – recording of behaviors that have been recorded systematically o Simplest method of scientific inquiry o Describe behavior and mental processes o Most widely used o Survey method – ask people’s opinions Case study – one individual Naturalistic observation – watch, describe Archival research – using already collected data - newspapers Clinical method – observe in clinic setting All have advantages and disadvantages Correlational Studies – Correlational method: measure two variables for statistical relationship – Variable: anything that can be assigned a numerical value – Uses quantitative measures Correlational Studies – Correlation coefficient • Measures each variable • – – Indicates strength ( - 1 to 0 to 1) and direction (negative or positive) of relationship Correlation does not mean causation – could be a third factor involved • Positive correlation – both factors increase • more study, better grades • Negative correlation – as one factor increases, the second factor decreases • More study, less recreation • No relationship (close to zero) – number of hours studied and height CORRELATION IS NOT CAUSATION • Lack of interest could be affecting test performance not hours studied Wednesday: Experimental research: • • Tests relationship of two or more variables – Allows conclusions about cause-and-effect – Quantitative measures of behavior compared in different conditions created by researchers – Evidence supports or rejects hypothesis Elements – Independent variable – gets manipulated – Dependent variable – amount of change – Experimental group – exposed to independent variable or conditions expected to create change – Control group – presents normal behavior used for comparison – Random assignment – Experimental control Summarize the four types of research and discuss the advantages and disadvantages Experimental: Manipulation and control of variables Purpose: identify cause and effect Advantages: Allows researchers precise control over variables Can identify cause and effect Disadvantages: Ethical concerns, practical limitations, artificiality of lab condition, uncontrolled variables confound results, researcher and participant biases Descriptive Research: naturalistic observation, case studies, surveys Purpose: observe, collect and record data Advantages: Minimizes artificiality, easier to collect data, allows description of behavior and mental processes as they occur Disadvantages: Little or no control over variables, researcher and participant biases cannot explain cause and effect Correlational research: statistical analyses of relationships between variables Purpose: identify relationships and how well one variable predicts another Advantages: helps clarify relationships between variables that cannot be examined by other methods and allows prediction Disadvantages: researchers cannot identify cause and effect Biological research: Studies the brain and other parts of the nervous system Purpose: identify causation as well as description and prediction Advantages: shares many of the advantages of experimental, descriptive, correlational research Disadvantages: shares many of the disadvantages of experimental, descriptive, correlational research Hand out article and worksheet – for Tuesday Thursday: Spend period reviewing for exam – go into computer lab and using quizlet.com (a flashcard and study game website) go over the material for the exam Friday: Exam – Units 1-4 Monday: November 15, 2010 Watch video on Intelligence Unit – learner.org Tuesday, November 16, 2010 Work on article worksheet – read article, fill out answers Wednesday, November 17, 2010 Discuss experimenter and subject biases: • Internal validity – the extent to which changes in the dependent variable can be attributed to the independent variable • Confounding variable – a variable whose unwanted effect on the dependent variable might be confused with that of the independent variable • – Subject bias – what the subject expects the study to be about – Experimenter bias – what the researcher expects – Experimenter effects – the personality, dress – Pygmalion effect – the subject performs better because of experimenter Double blind technique Types of Random Assignment • Placebo control – Placebo effect: provides no active effect – Use in identical conditions for control and experimental groups – Blind experiment – Researchers blind to group membership of participants to rule out experimenter bias – Strongest experiments – double blind – Researchers and participants kept blind Thursday, November 18, 2010 Descriptive statistics – how do we understand the data? • Central tendency asks what the average score is like in the distribution of scores • – Mean: Statistical average of all scores – Median: The fiftieth percentile (half of the scores are above this score, half are below) – Mode: The most frequent score Variability asks how dispersed the scores are relative to the average score or mean – • • Standard deviation: How far the average participant score deviates from the average (square root of the variance) Standard score – (z score) – scores on a normal curve can be described as their distance from the mean of the distribution using SD units – It allows you to compare scores from different distributions Percentile – The score at or below which a particular percentage of scores fall Friday, November 19 • Skewness - when scores are bunched up on either side of the bell curve LOOK AT THE TAIL OF THE SKEW – Scores bunched at the high end = negative skew • – Test is too easy Scores bunched at the low end = positive skew • Test is too hard Is the difference between the two groups caused by our manipulation or by chance? • We test the null hypothesis – we predict that there will be no effect of the independent variable No difference btw the groups – fail to reject the null hypothesis – Difference between the two groups – reject the null hypothesis – BUT IS THIS BY CHANCE OR FOR REAL? We are looking for true difference between groups – a statement of probability the larger the difference between the groups, the more likely it is not by chance. – Psychologists accept .05 as being statistically significant A probability of less than 5% that the results occurred by chance The results are more likely to be statistically significant if: Samples are large • • – The differences between the two means is large – The variability within the groups is small Internal validity – the extent to which changes in the dependent variable can be attributed to the independent variable rather than a confounding variable External validity – the extent to which the results of a research study can be generalized Reliable – safe to generalize from a sample Representative sample – More cases are better than fewer – • • •