EPPP Statistics

Question 1

Trend analysis

Answer 1

analysis of variance that is used to assess linear and nonlinear trends when the independent variable is quantitative.

Question 2

Mixed Designs

Answer 2

type of factorial design in which at least one IV is a between-groups variable and one IV is a within-subjects variable

Question 3

Regression Analysis

Answer 3

used to predict a score on one criterion based on the person’s obtained score on one predictor

involves identifying the location of the regression line (“line of best fit”) and using the equation for that line

Question 4

least squares criterion

Answer 4

used in regression analysis to locate the regression line

Question 5

MANOVA

Answer 5

used to examine differences in multiple dependent variables across groups, based on one or more independent variables

Question 6

Within-Subjects Designs

Answer 6

each subject receives, at different times, each level of the IV so that comparisons on the DV are made within subjects

Question 7

Type I And Type II Errors

Answer 7

I - true null hypothesis is rejected (= alpha)

II - false null hypothesis is retained (= beta)

Question 8

Factorial Design

Answer 8

2+ IVs

main effect - effect of a single IV on the DV
interaction - effects of one IV at different levels of another IV

Question 9

ANCOVA

Answer 9

version of ANOVA that statistically removing variability in the DV that is due to an extraneous variable

each person’s score on the DV is adjusted on the basis of his or her score on the extraneous variable

Question 10

Central Limit Theorem

Answer 10

sampling distribution of the mean
(a) will approach a normal shape as the sample size increases
(b) has a mean equal to the population mean
(c) has a standard deviation equal to the population standard deviation divided by the square root of the sample size (this is called the standard error of the mean)

Question 11

Experimental research

Answer 11

conducting an empirical study to test hypotheses about the relationships between independent and dependent variables

true - more control, random assignment

quasi - less control

Question 12

Chi-Square Test

Answer 12

comparing frequency of observations in nominal data

single-sample - one variable (TOTAL)
multiple-sample - more than one variable

Question 13

Systematic Error

Answer 13

predictable error

extraneous variables

Question 14

Cross-Validation

Answer 14

validating a correlation coefficient on a new sample

tends to shrink the coefficient

shrinkage is greatest when the original sample is small and the number of predictors is large

Question 15

Probability Sampling

Answer 15

each element in the target population has a known chance of being selected for inclusion in the sample

simple random sampling, stratified random sampling, and cluster sampling

Question 16

Single-subjects design

Answer 16

at least one A (baseline) and one B (treatment) phase

multiple measurements of the DV at regular intervals during each phase

reversal designs - 2+ baseline phases and one treatment phase (e.g., an ABA or ABAB), with the treatment being withdrawn

Question 17

Path Analysis

Answer 17

used to verify a pre-defined causal model or theory

Question 18

Cluster Analysis

Answer 18

group people or objects into a smaller number of mutually exclusive and exhaustive subgroups (clusters) based on their similarities

Question 19

Areas Under The Normal Curve

Answer 19

68% of observations - plus and minus one standard deviation from the mean

95% - plus and minus two standard deviations from the mean,

99% - plus and minus three standard deviations from the mean

Question 20

Rejection and Retention Regions

Answer 20

Rejection - contains the sample means that are unlikely to be obtained simply as the result of sampling error (size determined by alpha)

Retention - contains the values that are likely to be obtained simply as the result of sampling error (size = 1- alpha)

Question 21

Factorial ANOVA

Answer 21

two or more IVs (i.e., when the study has used a factorial design) and a single DV that is measured on an interval or ratio scale

“way” = number of IVs

Question 22

Between-groups designs

Answer 22

administering each level or combination of levels to a different group of subjects

Question 23

Standard Deviation

Answer 23

measure of dispersion (variability) of scores around the mean of the distribution

Question 24

Random error

Answer 24

error that is unpredictable (random)

Sampling error and measurement error

Question 25

Statistical Power

Answer 25

probability of rejecting a false null hypothesis increased by having a large sample, maximizing the effects of the IV, increasing the size of alpha, and reducing error

Question 26

randomized block ANOVA

Answer 26

extraneous variable treated as another IV (blocking) allows an investigator to statistically analyze the main and interaction effects of the extraneous variable

Question 27

ANOVA

Answer 27

used to compare the means of two or more groups when a study includes one IV and one DV that is measured on an interval or ratio scale yields an F-ratio that indicates if any group means are significantly different When the treatment has had an effect, the F-ratio is larger than 1.0 f ratio = (treatment effects + error) / error

Question 28

Internal Validity

Answer 28

allows an investigator to conclude that there is a causal relationship between IV and DV

Question 29

Threats to internal validity

Answer 29

Maturation - physical or psychological process or event occurs as the result of the passage of time and has a systematic effect on subjects' status on the DV History - an event that is external to the research study affects subjects' performance on the DV in a systematic way. Statistical regression - subjects are selected to participate because of their extreme status, tendency of extreme scores to "regress to the mean" on retesting Selection - when groups differ at the beginning of the study because of the way subjects were assigned to groups

Question 30

Multiple Regression

Answer 30

used for predicting a score on a continuous criterion based on performance on two or more continuous and/or discrete predictors output is a multiple correlation coefficient (R) and a multiple regression equation

Question 31

multicollinearity

Answer 31

High correlations between predictors ideally want low correlations between predictors and high correlations with criterion

Question 32

Moderator and Mediator Variables

Answer 32

Moderator - affect the strength or direction of the relationship between independent and dependent variables Mediator - explain or account for the relationship between independent and dependent variables

Question 33

Mixed (Split Plot) ANOVA

Answer 33

type of factorial ANOVA that is used when a study includes at least one between-groups independent variable and one within-subjects independent variable.

Question 34

Event Sampling

Answer 34

useful for behaviors that are rare or that leave a permanent product It involves recording each occurrence of a behavior during a predefined or preselected event.

Question 35

Interval recording

Answer 35

method of behavioral sampling dividing a period of time into discrete intervals and recording whether the behavior occurs in each interval particularly useful for behaviors that have no clear beginning or end

Question 36

Effect Size

Answer 36

magnitude of the relationship between independent and dependent variables

Question 37

Cohen's d

Answer 37

measure of effect size difference between two groups in terms of standard deviation units

Question 38

eta squared

Answer 38

measure of effect size indicates the percent of variance in the dependent variable that is accounted for by variance in the independent variable

Question 39

Experimentwise Error Rate

Answer 39

probability of making one or more Type I errors (false positives) across a set of statistical tests conducted within a single experiment less tests you run, the better your rate

Question 40

Parametric and Non-Parametric Tests

Answer 40

Parametric - interval/ratio scale, normal distribution, homoscedasticity More powerful Non-parametric -nominal/ordinal scale

Question 41

homoscedasticity

Answer 41

population variance are equal

Question 42

Sampling Distribution of the Mean

Answer 42

distribution of sample means that would be obtained if an infinite number of equal-size samples were randomly selected from the population and the mean for each sample was calculated used to determine how likely it is to obtain a particular sample mean given the population mean, the population SD, the sample size, and the level of significance

Question 43

External Validity (& threats)

Answer 43

generalizability threats -pretest sensitization (when pretesting affects how subjects react to the treatment) -reactivity (when subjects respond differently to a treatment because they know they are participating in a research study) -multiple treatment interference (which occurs when subjects receive more than one level of an IV) Counterbalancing can be used to control multiple treatment interference and involves administering different levels of the IV to different groups of subjects in a different order.

Question 44

Scales Of Measurement

Answer 44

nominal - frequencies ordinal - ordered categories interval - ordered, with equal intervals ratio - ordered, equal intervals, true zero

Question 45

Skewed Distributions

Answer 45

positively - lower scores (mode, median, mean) negatively - higher scores (mean, median, mode)

Question 46

Measures of Central Tendency

Answer 46

mean - interval or ratio median - ordinal data (and with interval and ratio data when the distribution is skewed or contains one or a few outliers) mode - nominal

Question 47

Shared Variability

Answer 47

A correlation coefficient for two or more variables can be squared to obtain a measure of shared variability rxy = .5 then 25% of variability in Y due to X

Question 48

Discriminant Function Analysis

Answer 48

two or more continuous predictors will be used to predict or estimate a person's status on a single discrete (nominal) criterion

Question 49

Alpha

Answer 49

probability of rejecting the null hypothesis when it is true (making a Type I error)