Research Methods and Stats Flashcards
A ___ variable affects the direction or strength of the relationship between IV and DV; whereas a _____ variable EXPLAINS the relationship between the IV and DV
A moderator variable affects the direction or strength of the relationship between IV and DV; whereas a mediator variable EXPLAINS the relationship between the IV and DV
A frequency polygon is helpful for what type of data?
Interval (difference between categories or level is equal) or Ratio (difference between categories is equal AND there is an absolute 0)
Freq. polygon is interpreted as normal or non-normal
Normal distribution: percentile of scores with 1SD, 2SD: 3SD
68, 95, 99
Leptokurtic distribution
Platykurtic distribution
Leptokurtic distribution: more scores piled up in middle so sharp peak and flatter tails
Platykurtic distribution: flatter in middle and thicker tails
Differential selection
differential assignment of subj to treatment groups where the groups differ at the beginning of the study due to the way they were assigned to groups (i.e., soccer players already had better eye movement ability at the beginning); a threat to internal validity; addressed with random assignment
History, maturation, differential selection, statistical regression to the mean are all examples of what
threats to internal validity
Solomon 4 group design
used to identify the effects of pretesting on a study’s internal and external validity; the study includes 4 groups (2 groups take pretest, 2 groups take posttest)
The CPT-2 changing to the CPT-3 for patients in the same research sample is an example of
Instrumentation
Experimenter expectancy and demand characteristics are both examples of
Reactivity; threatens external validity
Whta do grounded theory, thematic analysis, and phenomenology have in common?
They all involve interviews.
Grounded theory - come up with a theory based on participant views
Phenomenology - gain an in-depth look at the lived experience of participants
thematic analysis - look for patterns within interviews
ethnography
study and observe and participate in culture and groups in their setting
Is triangulation qualitative or quantitative
Both - using multiple types of sources of evidence to understand a topic
When does the treatment phase occur in single subject design
The treatment phase does not usually begin until a stable pattern of performance on the dependent variable is established during the baseline phase
The primary characteristic that distinguishes true experimental research from quasi-experimental research is that, when conducting a true experimental research study, the researcher is able to:
randomly assign subjects to different treatment groups.
homoscedasticity
homoscedasticity – assumption of regression that the variability of criterion scores is similar for all predictor scores
If one variable is continuous and the other is a dichotomous variable, what type of regression do you use?
point biserial correlation coefficient
*biserial correlation coefficient is used when one variable is continuous and the other is an artificial dichotomy. An artificial dichotomy occurs when a continuous variable is dichotomized. Final exam scores represent an artificial dichotomy when a cutoff score is used to divide the scores into two categories – pass and fail.
Discriminant function analysis is used when two or more predictors will be used to examine their effect on what type of outcome?
Nominal variable (group status)
Example: how do symptoms of depression, anxiety, and alcohol use freq predict smoking versus non smoking status
____ is the alternative to the Pearson r for calculating the correlation between two continuous variables when the variables have a nonlinear relationship.
Eta
If you reject a true null hypothesis or retain a false null hypothesis, you are making
An incorrect decision (Type I error (alpha) or type II error (beta))
the ability to reject a false null hypothesis
statistical power; the larger the alpha, the bigger the sample, and the larger the effect size, the greater the power
The central limit theorem predicts that the sampling distribution of means increasingly approaches normal as the sample size
sample size increases regardless of the shape of the population distribution.
Formula for SEM
population SD/sq. root of sample size
A non-parametric test deals with non-normal data but also
nominal and ordinal data and include the chi-square test
Biggest diffence between t-test and one-way ANOVA?
t-test you can only have two groups (CBT vs. ACT) whereas one-way ANOVA you can have 2+ (CBT vs. ACT vs. Client Centered)
F-ratio; what is it and when do you know that the IV has had an effect on the DV
F = MSB (mean square between)/MSW (mean square within)
MSB = variability due to tx + error MSW = variability due to error
F > 1 = effect of IV
Experimentwise error rate ____ the more statistical tests you run
Increases
Effect size is a practical significant test; Cohen’s d is often used and is calculated by
(Mean Group 1 - Mean Group 2)/SD of both groups combined
What is the difference between a one-way, two-way, and three-way ANOVA
The number of IVs
one way = Effect of SES on BMI
two-way = Effect of SES and Age on BMI
three-way = Effect of Age, SES, and diet on BMI
Median should be used instead of mean for
skewed data
Can you use a chi-sqare for repeated observations
No
Idiographic research design
single subject
A researcher would use the split-plot ANOVA to analyze the data she collected in her research study when:
C. her study included one between-subjects independent variable and one within-subjects independent variable.
canonical correlation
appropriate multivariate technique when two or more predictors will be used to estimate status on two or more criteria.
The central limit theorem predicts that, regardless of the shape of the population distribution of scores, a sampling distribution of means increasingly approaches the shape of:
a normal distribution as the sample size increases.
