# Shared Flashcard Set

## Details

Experimental Psych -Chp. 8-13
Research Deesign, ANOVA, T-Tests
41
Psychology
03/17/2010

Term
 T-Test
Definition
 t-test allows us to compare the means of two groups and determine how likely the difference between the two means occurred by chance.
Term
 Paired (or correlated) T-test
Definition
 is concerned with the difference between the average scores of a single sample of individuals who is assessed at two different times (such as before treatment and after treatment) or on two different measures. It can also compare average scores of samplesof individuals who are paired in some way (such as siblings, mothers and daughters, persons who are matched in terms of a particular characteristics).
Term
 Analysis of Variance (ANOVA)
Definition
 2+ more groups being tested. Tests your Null Hypothesis and your alternative hypothesis. It will tell your the difference, but it will not tell you how or which one differs.
Term
 Inflated alpha:
Definition
 If you do too many tests on one set of data. If you do three tests then you’d divide your p value= 0.05/3 and that would become your new alpha level or pvalue =.017
Term
 Chi-square
Definition
 % or frequencies
Term
 Casual Conclusion
Definition
 if there is manipulation and random assignment. – has to be a true exp.
Term
 How do you know when you have an interaction
Definition
 If the lines are not paralell, then you have an interaction, even if they are not crossing, they will be crossing eventually
Term
 Significance
Definition
 tells you if your data can be applied to the general population or is a result of error.
Term
 Main Effect
Definition
 The effect of each of the independentvariables on the dependent variable is the main effect of that variable
Term
 Internal Validity
Definition
 Internal validity refers to the scientificaccuracy of the study or procedure
Term
 Confoudning Variables
Definition
 threats to internal validity; fatigue, maturation, mortalitiy rate, practice effect, boredum
Term
 Posttest Only Independent GroupsDesign
Definition
 Classic experimental design, two equal groups, randomly tested, no selection differenece,than intro. IV(manipulation) to exp and control group, and then easure effect of IV on DP
Term
 Pretest-Posttest IndependentGroups Design
Definition
 Design:Group A Pretest- Treatment- PosttestGroup B Pretest- Control - PosttestAllows you us to see if a change actually occured. difference=(Posttest-Pretest, Allows paticipants with a paticular characteristic. But pretest can effect postest(practice effect, fatigure, maturation, hoistory)
Term
 Solomon’s Four-Group Design
Definition
 Group A Pretest -Treatment -Posttest Group B Pretest -No Treatment -Posttest Group C Treatment -Posttest Group D No Treatment -PosttestAllows us to assess whether there is aninteraction between the treatment and thepretest If no impact of pretest, posttest scores will be same inboth control groups and both exp groups
Term
 Matched Pairs withRandom Assignment
Definition
 match variable from each individual, match on relevant variables ( variables likley to affect the dependent measure, show variability in the population
Term
 Repeated Measures
Definition
 Do BOTH MANIPULATION IN ONE GROUP, Each participant goes through all experimental conditions. Get baseline (control) measure of DV Apply independent variable (manipulation) Take another measure of DV. Design:Control Measure1 Treatment Measure2 Get a difference score Measure2 – Measure1 = Difference
Term
 Order Effects
Definition
 When the order of the treatment has an effect on the treatment. To get rid of this use Latin square design. gp1-pretest-treatment-test-control-postestgp2-pretest-control-test-treatment-posttest
Term
 Random Assignment
Definition
 Critical to internal validity. Assignment procedures; free random assignment to groups, matched random assignemnt in matched sets to group
Term
 Subject Effects/Reactivity
Definition
 Changes in behaviour simply from being studied; physiological changes
Term
 Demand Characteristics/social desirability
Definition
 Change their behaviour and performance, because they form an opinion of what the experimentor meant
Term
 Placebo Effect
Definition
 Treatment effect that is due to expectation that the treatment will work
Term
 Control Procedures
Definition
 Keep testing conditions constand for all participants; time of day, lightning, setting, experimenter, instructions given, distractions
Term
 How to Control Procedures
Definition
 Control throug the selection and assignment of participants (random or matched), response measurements,replication, Automation ( reduces contact btw participants and exp.), Using objective measures(less judgement by the exper.)
Term
 Single Blind
Definition
 The participant dose not know what condition they are in.
Term
 Double Blind
Definition
 Neither the experimenter nor the participant knows what condition the participant is in.
Term
 Multilevel, randomized, between-subjects design.
Definition
 Group 1 Pretest Treatment 1 Posttest Group 2 Pretest Treatment 2 Posttest Group N Pretest Treatment N Posttest May or may not include a pretest Multi-group extension of the basic experimentaldesigns
Term
 Factorial Designs
Definition
 Includes two or more IV (essentially 2+ studies in one), interactions effects of the IV
Term
 Interaction
Definition
 The combined effects of two or more independent variables on the dependent variable is an interaction
Term
 Repeated-Measures Factorials
Definition
 Can use a within-subjects(repated measures) desgin in a factorial study. Increases ability to find a significant effect
Term
 Mean
Definition
 the average score
Term
 Median
Definition
 Middle numbers
Term
 Mode
Definition
 Most frequently occuring number
Term
 Range
Definition
 Difference between the largeest and smallest score in a set
Term
 Variance
Definition
 Average distance of the scores from the mean of the set of scores
Term
 Standard Deviation
Definition
 square root of variance
Term
 Pearson product-moment correlation
Definition
 Measure of relationshhips - with interval or ratio data
Term
 Spearman rank-order correlation
Definition
 measure of relationship- used when one variable is ordinal and tbe second is at least ordinal
Term
 Scatter Plot
Definition
 Visual representation of a correlation, helps to identify nonlinear relationships
Term
 Regression
Definition
 finding the best fitting straight line for the data, best in scatter plot
Term
 Inferential Statistics
Definition
 Used to draw inferences about population on the basis of samples fom the populations. the data we do on our data is called the inferential statistics
Term
 Testing for Mean Differences
Definition
 T test (for independent groups), Paired t-test, ANOVA
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