PSY3213C Research Methods in Psychology Exam 3 PARTIAL Study Guide NOTE Exams may contain material not included on this guide Material on guide is not guaranteed to be on exams Use this information as a GUIDE for your studying but do not treat it as a map that will show you everything This information comes from the textbook AND the lectures Step 1 Be able to answer ALL of the Check Your Understanding Questions from the Chapters covered in this book Chapter 9 Introduction to Simple Experiments Be able to recognize if an experiment meets criteria for establishing causation o Has to pass the 3 tests Covariance Temporal Precedence Internal Validity What is a matched group design o In a matched groups design with three groups participants are sorted from lowest to highest on some trait They are then assigned at random to experimental groups o Help control for error variance o Controls participant related variability by matching groups on characteristics that What is the difference between within subject design and between subject design influence performance o Between Subjects Designs Aka Independent groups design Different groups of participants are exposed to different levels of the independent variable Advantages Simple Disadvantages o Relatively few participants required o Data and stats easy easy to interpret o No pre testing required to ensure equality of groups Doesn t provide a large amount of info o Differences but not shape of function relating IV and DV May be insensitive to effects when participants differ greatly in their performance o Within Participant Designs Aka Within groups designs All participants are exposed to all levels of the independent variable Advantages Reduces error variance due to individual differences among subjects across treatment groups o Effects of independent variable are more likely to be detected Requires fewer participants Disadvantage More demands put on participants longer study more complicated study may increase drop out rate When participants do drop out all their data is unusable Mistakes more costly again because you lose a large amount of data CARRY OVER EFFECTS What is carryover and what are the six different types of carryover effects for within subject designs o Carryover A major issue of within participant designs Carryover effects Exposure to a previous treatment affects performance in a subsequent treatment also called order effects Carryover effects are not an issue in between participant designs o 6 sources of carry over effects 1 Learning Learning a task in the first treatment may affect performance in the second irrespective of IV 2 Fatigue Earlier treatments may affect performance in later treatments because participants will get tired 3 Habituation Repeated exposure to a stimulus may lead to unresponsiveness to that stimulus 4 Sensitization Exposure to a stimulus may make a subject respond more strongly to another 5 Contrast Participants will compare the current treatment to treatments that came before 6 Adaptation Physiological changes over time based on experimental setting What are potential ways to deal with carryover effects o There are 3 ways to deal with carryover Counterbalancing Try to minimize carryover effects Treatment order as an IV What different methods are there of counterbalancing and what are the advantages disadvantages of each Counterbalancing Advantages all possible combinations of treatments are represented Disadvantages minimum number of subjects can get large fast Random Order Counterbalancing Advantages assign random order of treatment for each participant Disadvantages carry over effects may not completely balance likelihood of treatment effects being the result of carryover effects small o What is a Latin square design and how is it useful How to make a Latin Square Randomize conditions then pair them with digits Generate first row using formula Generate other rows by adding 1 to each number in the preceding row Controls for ordinal position of each treatment Each condition precedes or follows each other condition once Chapter 10 More on Experiments Confounding and Obscuring Variables Be able to describe the multiple threats to internal validity in class You won t need to list define them but you ll need to identify them and or be able to know the differences among them o Ex You are unable to use data from 20 of the participants you recruited because they got sick and were unable to complete the second phase of your data collection Is this a problem of history maturation attrition or regression o History o Maturation o Testing o Reactive Something besides treatment happens between pretest and protest Events that occur between the DV measurements in a repeated measures design pretest posttest Ex Noise or laughter during a lengthy experimental session Your participants naturally change over course of study Changes in participants that occur over time during an experiment These changes could include actual physical maturation or tiredness boredom hunger and so on Your posttest changes b c of experience w pretest practice effect Because measuring the DV causes a change in the DV The measurement itself attitude questionnaire causes change in the DV subject knows what s going on and can answer however they want DV measurements that actually change the DV being measured Many attitude questionnaires are reactive measurements The experimenter him herself could affect answers Change in instrument or experimenter thru course of experiment When the equipment or human measuring the DV changes the measuring criterion over time Less likely these days that your equipment will begin to fail o Instrumentation o Regression Change in posttest score from extreme to less extreme Originates with statistical concept called regression toward the mean Extremely low scores improve or extremely high scores fall on a second administration of a test due solely to statistical reasons Extremes are rarely replicated When groups are not the same to begin with o Selection o Attrition When lose participants from groups especially more from one group than the other or more extreme scorers Morality can occur if experimental participants from different groups drop out of the experiment at different rates o Diffusion of treatment Control group becomes familiar with treatment How does generalizability relate to problems associated with external validity o Results not being able to be used outside the testing environment o The results
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