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42 Cards in this Set
 Front
 Back
Formula for the standard error of the mean

Standard Deviation
 square root of sample size 

To increase the standard error of the mean, what do you need to do to the sample size and standard deviation?

Decrease the number of individuals in the sample size and increase the standard deviation.


Define Selection

Preexisting subject differences that threaten the internal validity of a research study...these could account for differences between the groups on the dependent variable.


What is Path Analysis

A way to test assumptions about the causal relationships among multiple variables without actually manipulating variables and doing a true experiment.


F Ratio

MSBmean square between (between group variance)
 MSWwithingroup variance 

What is a factorial design?

Several independent variables are assessed at the same time. It allows for the interaction of several variables to be assessed.


What does LISAREL mean?

Linear Structural Relationships. A structural equation modeling techniquedesiged to assess the degree to which a causal model involviing multiple variables is supported by observed data.


What does LISREL involve?

Latent and observed variables. Unidirectional and bidirectional causal relationships.


Regression to the mean

The tendency of extreme values or characteristics to be less extreme.


Pearson r

The relationship between X and Y variables can be depicted on a scatterplot as a straight line.


Name several threats to internal validity

Maturation
Testing Instrumentation Selection Statistical Regression 

Maturation

Any internal change that occurs in the subjects while the experiement is in progress. I.e., getting hungry, tired, etc.


History

Any external event that affects scores or status on the dependent variable.


Instrumentation

A change in DV may be observed from pretest to posttest because the nature of the measuring instrument has changed. I.e., the scale broke.


Rosenthal Effect
(Pygmalion Effect) 
Behavior of subjects changes as a result of experimenter expectancies, i.e., teacher expectations.


Hawthorne Effect

Tendency of subjects to behave differently due to the mere fact that they are participating in research, i.e, changing the work environment.


CrossSequential Study

Involves studying groups of subjects that are divided on the basis of age. Involves studying them for a period of time. Controls for cohort effects, less costly than longitudinal studies.


Multiple Baseline Study

A singlesubject study that involves the sequential application of a treatment across different baselines. Does not entail withdrawal of treatment.


Onegroup timeseries

Administering multiple pretests and posttests to one group of subjects before and after a treatment is administered. Controls for maturation, testing, and regression.


What is power?

The probability of rejecting a false null hypothesis, or detecting a true effect of the independent variable.


How would you increase power?

Increasing reliability, or decreasing error variance reduceds the power that you will "miss" a true effect.


Central Limit Theorem

Predicts that as sample size increases, the shape of the sampling distribution of means approaches normality, regardless of the shape of the population distribution.


Scheffe Test

Posthoc test that is considered to be the most conservative. Most likely to result in a type II error.


Type II error

Incorrect retention of the null hypothesis.


Canonical Correlation

Used to identify the relationship between multiple predictors and multiple criterion variables.


Validity

Looks at accuracy...does the measure what it purports to measure.


Trend Analysis

Quantitative independent variable, nonlinear. Repeated measures design.


Formula for ZScore

(X) Raw Score  (M) Mean
 Standard Deviation 

Percentile Ranks (PR)

Flat or rectangular distribution; nonlinear


Type I Error

Rejecting a true null hypothesis. Thinking you have something when you don't.


Alpha Level

The probability of making a type I error. Level of significance.


Type II Error

Retaining a false null hypothesis. Thinking you don't have something when you really do.


Beta Level

Probability of making a type II error.


Power

The probability of rejecting the null hypothesis when it is false...saying there is a difference when there really is a difference.


Name four ways to increase power:

1. Increase the sample size
2. Increase alpha 3. Use a onetailed test 4. Increase the difference of the population means under study. 

MannWhitney U

A nonparametric test that's equivalent to an independent samples ttest.


Demand characteristics

Cues in the experimental setting that allow subjects to deduce the experimental hypothesis.


Quasiexperimental research

Subjects are not randomly assigned to treatment groups. This threatens internal validity.


Percentile ranks

Always have a rectangular or flat, distribution. The same number of scores fall within any given range.


ZScores

Any distribution can be converted into zscores. The zscore distribution will maintain the shape of the original distribution. The mean always = 0 and the SD = 1.


Power

The probability of rejecting a false null hypothesis. Can it detect a true difference between population means.


ChiSquare

Research that involves categorizing observations. Do obtained frequencies differ?
