Term

Definition
ttest 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) Ttest 

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 samples of 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

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 


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Definition
if there is manipulation and random assignment. – has to be a true exp. 


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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 


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Definition
tells you if your data can be applied to the general population or is a result of error. 


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Definition
The effect of each of the independent variables on the dependent variable is the main effect of that variable 


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Definition
Internal validity refers to the scientific accuracy of the study or procedure 


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Definition
threats to internal validity; fatigue, maturation, mortalitiy rate, practice effect, boredum 


Term
Posttest Only Independent Groups Design 

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
PretestPosttest Independent Groups Design 

Definition
Design: Group A Pretest Treatment Posttest Group B Pretest Control  Posttest Allows you us to see if a change actually occured. difference=(PosttestPretest, Allows paticipants with a paticular characteristic. But pretest can effect postest(practice effect, fatigure, maturation, hoistory) 


Term
Solomon’s FourGroup Design 

Definition
Group A Pretest Treatment Posttest Group B Pretest No Treatment Posttest Group C Treatment Posttest Group D No Treatment Posttest Allows us to assess whether there is an interaction between the treatment and the pretest If no impact of pretest, posttest scores will be same in both control groups and both exp groups 


Term
Matched Pairs with Random Assignment 

Definition
match variable from each individual, match on relevant variables ( variables likley to affect the dependent measure, show variability in the population 


Term

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

Definition
When the order of the treatment has an effect on the treatment. To get rid of this use Latin square design. gp1pretesttreatmenttestcontrolpostest gp2pretestcontroltesttreatmentposttest 


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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

Definition
Treatment effect that is due to expectation that the treatment will work 


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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

Definition
The participant dose not know what condition they are in. 


Term

Definition
Neither the experimenter nor the participant knows what condition the participant is in. 


Term
Multilevel, randomized, betweensubjects 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 Multigroup extension of the basic experimental designs 


Term

Definition
Includes two or more IV (essentially 2+ studies in one), interactions effects of the IV 


Term

Definition
The combined effects of two or more independent variables on the dependent variable is an interaction 


Term
RepeatedMeasures Factorials 

Definition
Can use a withinsubjects(repated measures) desgin in a factorial study. Increases ability to find a significant effect 


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Definition


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Definition
Most frequently occuring number 


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Definition
Difference between the largeest and smallest score in a set 


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Definition
Average distance of the scores from the mean of the set of scores 


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Definition


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Pearson productmoment correlation 

Definition
Measure of relationshhips  with interval or ratio data 


Term
Spearman rankorder correlation 

Definition
measure of relationship used when one variable is ordinal and tbe second is at least ordinal 


Term

Definition
Visual representation of a correlation, helps to identify nonlinear relationships 


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Definition
finding the best fitting straight line for the data, best in scatter plot 


Term

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 ttest, ANOVA 

