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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
Pre-existing 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
MSB--mean square between (between group variance)
MSW--within-group 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 technique--desiged 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
Statistical Regression
Any internal change that occurs in the subjects while the experiement is in progress. I.e., getting hungry, tired, etc.
Any external event that affects scores or status on the dependent variable.
A change in DV may be observed from pretest to post-test 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.
Cross-Sequential 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 single-subject study that involves the sequential application of a treatment across different baselines. Does not entail withdrawal of treatment.
One-group time-series
Administering multiple pretests and post-tests 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
Post-hoc 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.
Looks at accuracy...does the measure what it purports to measure.
Trend Analysis
Quantitative independent variable, non-linear. Repeated measures design.
Formula for Z-Score
(X) Raw Score - (M) Mean
Standard Deviation
Percentile Ranks (PR)
Flat or rectangular distribution; non-linear
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.
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 one-tailed test
4. Increase the difference of the population means under study.
Mann-Whitney U
A nonparametric test that's equivalent to an independent samples t-test.
Demand characteristics
Cues in the experimental setting that allow subjects to deduce the experimental hypothesis.
Quasi-experimental 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.
Any distribution can be converted into z-scores. The z-score distribution will maintain the shape of the original distribution. The mean always = 0 and the SD = 1.
The probability of rejecting a false null hypothesis. Can it detect a true difference between population means.
Research that involves categorizing observations. Do obtained frequencies differ?