Research Flashcards
quasi-experiment
uses preexisting groups
the IV cannot be altered (ex: gender or ethnicity)
you cannot state that the IV caused the DV
an example of a quasi-experimental study: ex post facto
regression
or statistical regression
extremely high and low scores will regress toward the mean if the measure is given again
internal validity
whether the DVs were truly influenced by the experimental DVs or whether other factors had an impact (confounding factors/contaminating variables/extraneous variables)
external validity
generalizability
parsimony
the best explanation is the easiest and least complex
Occam’s Razor
synonymous with parsimony
interpret the results in the simplest manner
no matter the study, there will be flaws. minimize the worst ones
(car windshield sticker, bubbles)
all correlational research is said to be ____
confounded
1 periodical for research
APA’s Journal of Counseling Psychology
basic research
conducted to advance our understanding of theory
applied research
conducted to advance out understanding of how theories, skills, and techniques can be used in terms of practical application
AKA action research or experience-near research
IV vs DV
I manipulate the IV
DV is the Data our outcome
casual-comparative design
a true experiment except for the fact that groups were not randomly assigned; so you didn’t truly control the IV
data gleaned from the casual comparative can be analyzed with a test of significance (e.g. t-test or ANOVA) just like any true experiment
DV must be ____ measured
that which is directly measured
ex: you hypothesize that biofeedback will reduce anxiety and increase test scores. the DV is test scores because you’re not measuring anxiety in the experiment.
You need ___ participants for a true experiment
30
15 in control group, 15 in experimental group
Surveys need ___ people with a response rate of at least ____.
100 people
50-75%
organismic variable
a variable the researcher cannot control/manipulate, yet exists such as height, weight, gender
AKA status variable
___ pioneered hypothesis testing
R. A. Fisher
The null hypothesis states that
the IV does not affect the DV
experimental hypothesis
your hunch, that the IV does affect the DV
AKA affirmative hypothesis
t-test
used to determine if a significant difference between 2 means exists (on one variable)
find the “critical t” in a table
if your t value is above it, then you reject the null
if your t is below it, then you accept the null
between-subjects design vs. within-subjects design
between-subjects - uses different subjects for each condition
within-subjects - same subjects are studied (e.g., get a pre- and post-test after administering the IV)
parameter
a value obtained from a population
vs. statistic - a value drawn from a sample
P represents
probability or the level of significance
AKA alpha level
in research, P should be set at ___
P = .05 or lower
(e.g. .01, .001)
P = significance level
.05 might be referred to as “95% confidence interval”
A significance level of .05 means
the differences observed would occur via chance only 5 times out of 100
the probability of committing a Type I or alpha error is .05
the 95% confidence interval means
P = .05
the differences observed would occur via chance only 5 times out of 100
alpha error
AKA Type I error
When the researcher rejects the null when it is true
The probability of committing a Type I error is the level of significance
beta error
AKA Type II error
When the researcher accepts the null hypothesis when it is false
power of a statistical test =
1 - beta
power means the test’s ability to correctly reject the null hypothesis
think of Type I and II errors like
a seesaw
the risk of committing one error goes up when the other goes down
how to lower the risk of chance/error factors
increase the sample size
differences revealed via large samples are more likely to be genuine than differences revealed using a small sample size
ANOVA
use to compare the means of > 2 groups (as opposed to t-test) on one variable
the resulting value is an F-value
consult the F-value
if your F-value is higher, reject the null
if your F-value is lower, accept the null
positively skewed
mode < median < mean
negatively skewed
mode > median > mean
kurtosis
peakedness of a distribution
kurtosis - types
leptokurtic - peaked
mesokurtic - normal
platykurtic - no peak, flat
dependent t-test
t-test where 2 similar groups are matched in some meaningful way, or the same group is tested twice
independent t-test
comparing 2 independent groups (that are usually assigned randomly) on one variable
independent groups might also be called unmatched/uncorrelated
a test for more than one IV and more than 2 groups
factorial ANOVA
Ex: if two treatments CBT and interpersonal therapy [IPT] are compared for effectiveness on males and females and different treatments were significantly more
effective with different genders—for example, CBT worked significantly better for males than females while IPT worked significantly better for females than males).
a test for more than one IV, more than 2 groups, where you want to control one of the IV’s
analysis of covariance
ANCOVA
e.g., examining the relationship between household income and work satisfaction, with gender as a covariate—that is, the statistical effects of gender are removed from the
analysis to control for any effects gender might have on work satisfaction
a test for more than one IV, more than 2 groups, and more than one DV
MANOVA (multiple)
a test for more than one IV, more than 2 groups, and more than one DV, controlling for one IV
MANCOVA (multiple)
parametric statistics
rely strictly on interval and ratio data
parametric tests are used when the following assumptions are met:
1. Data for the dependent variable(s) are approximately normally distributed.
2. Samples were randomly selected and/or assigned.
3. An interval or ratio scale of measurement was used for each of the variables involved in the study.
ex: t-test, ANOVA, factorial ANOVA, ANCOVA, MANOVA, MANCOVA
non-parametric statistics
used when we can’t make assumptions about distribution of true scores in the population like we can when we use parametric statistics
suggested when nominal or ordinal data are involved or when interval or ratio data are not distributed normally (i.e., are skewed).
ex: chi-square, Mann-Whitney U test, Kolmogorov-Smirnov Z procedure, Kruskal-Wallis test, Wilcoxon’s signed-ranks test, Friedman’s rank test
the non-parametric version of the ANOVA
Kruska-Wallis test
(so this will be an extension of the Mann-Whitney U-Test when there are more than 2 groups, just like the ANOVA expands the t-test)
the non-parametric version of the t-test when means are correlated
Wilcoxon’s signed-ranks test
want to test whether 2 “co-related” means differ - WilCOxon, “co”
synonymous with the dependent t-test
the non-parametric version of the t-test when means are uncorrelated
Mann-Whitney U-Test
want to test whether 2 Un-correlated means differ (U-Test, Un-correlated)
uses ordinal data instead of interval or ratio data
synonymous with the independent t-test
non-parametric version of Pearson’s r
Spearman correlation or Kendall’s tau
chi-square test
nonparametric
used with two or more categorical or
nominal variables, where each variable contains at least two categories that MUST be mutually exclusive. All scores must be independent
examines whether obtained frequencies differ significantly from expected frequencies
ex: the decision to terminate counseling (yes, no) and the gender of the professional counselor (male, female). A chi-square
would test whether the tallies for the decision to quit counseling by gender of counselor are significantly different from those expected in the population.
Kolmogorov-Smirnov Z procedure
nonparametric
use in place of Mann-Whitney U-Test when the sample size < 25
Friedman’s rank-test
Similar to Wilcoxon’s signed-
ranks test in that it is designed for repeated measures; also can be with more than two groups