Exam 3 Flashcards
Statistical Validity
The accuracy of p-value on which a statistical decision is based
Construct Validity
The degree to which the theory behind the research study provides the best explanation for the results observed
External Validity
The extent to which the results of a study generalize to other people, places, or conditions
Internal Validity
The extent to which we can be confident that the observed changes in the DV were due to the IV and not confounding variables
Maturation
Confounding Variable - Changes in the DV are due to the natural maturation of the participant
History
Confounding Variable - Changes in the DV that are due to historical events that occur during the study that are unrelated to and can’t be controlled by the study
Testing
Confounding Variable - Any change in a participant’s score on the DV due to being tested previously
Instrumentation
Confounding Variable - Any change in the calibration of the measuring instrument that affects DV scores
Regression to the Mean
Confounding Variable - Tendency for participants who are selected because they have extreme scores on a variable to be less extreme in a follow-up setting
Selection
Confounding Variable - Any factor that creates groups that are not equivalent at the beginning of the study
Attrition
Confounding Variable - Loss of participants during a study; differential loss is problematic because those who drop out are likely to differ from those who continue
Diffusion of Treatment
Confounding Variable - Change in the response of participants to a condition due to info gained about conditions from other participants
Sequence Effects
Confounding Variable - Effects on performance in later conditions that result from the experience one had from a previous study
Subject Effects
any changes in the behavior of participants that are attributable to being in the study rather than variables in the study
Demand characteristics
cues given to participants on how the researcher expects them to behave
placebo effect
when participants expect a specific effect of an experiment and they think it happens
Control
any procedure used to counteract potential threats to the validity of the research; often keeping other variables still or “constant”
Exact replication
repeating the study exactly as it was carried out originally
Systematic replication
testing a theoretical or procedural modification of the original procedure that will produce desired results only if the original findings were accurate
Conceptual Replication
generating and testing different research hypotheses from the same problem statement
Single-blind procedure
when the researcher working with the data doesn’t know which subjects are affected by what conditions; can be subjects kept in dark too
Double-blind procedure
when both the researcher and participants are blind to the assignment of each condition
Placebo
condition identical in appearance to the tested condition but has no effect
Automation
automatic running of procedures like data recording and giving instructions to reduce experimenter contact bias
Objective measure
measure based on empirically observable and clearly observable events people can agree on
Percent agreement
test of inter rater reliability
Deception
withdrawing study info till the end
Balanced placebo design
using deception on both groups about if anyone receives a placebo
General population
group of all organisms, events, and things we are interested in
Target population
subset population the researcher is primarily is interested in; this is the population we want to generalize our findings to
Accessible population
subset of target pop that is available to the researcher
Sample
subset of accessible pop on which measures are taken
Representative sample
sample that adequately reflects population characteristics
Random sampling
drawing sample so that every member of the population has an equal chance to be selected and the selections don’t change each other
Stratified random sampling
drawing separate random samples from several populations
ad hoc sampling
drawing participants randomly from an accessible population
Free random assignment
assigning participants to conditions in a random manner so that one assignment does not affect the other
Randomization within blocks
randomly assigning participants in blocks of conditions so that we have one participant in each condition before we move on to assign more to the next block of conditions
Matched random assignment
matching participants on a relevant variable and then randomly assigning the matched participants to group with one matched participant per group
Other matching procedures
matching by group characteristics rather by by individual characteristics; equating groups by holding the variable constant; building in the variable as another factor
Analysis of variance (ANOVA)
hypothesis-testing procedure for studies with three or more groups
Within-groups estimate of the pop variance
estimate of the variance of the population of individuals based on the variation among the scores in each of the actual groups studied
between-groups estimate of the population variance
estimate of the variance of the population of individuals based on the variation among the means of the groups studied
F ratio
ration of the between groups population variance estimate to the within-groups population variance estimate
F distribution
mathematically defined curve that is the comparison distribution for ANOVAs
F table
table of cutoff scores on the F distribution
S^2 or MSwithin
within-groups estimate of the population variance
grand mean (GM)
overall mean of all the scores regardless of what group they are in; when group sizes are equal, mean of the group means
S^2between or MSbetween
between-groups estimate of the population variance
between groups (numerator) degrees of freedom
df used in the between-groups estimate of pop variance; numerator; number of scores free to vary in figuring the between groups estimate
within groups (denominator) degrees of freedom
df used in the within groups estimate; denominator; number of scores free to vary in figuring the within groups estimate
planned contrast
comparison in which the particular means to be compared were decided in advance; also called planned comparison
Bonferroni procedure
multi comparison procedure in which the total alpha percentage in divided among the set of comparisons so that each is tested at a more stringent significance level
post hoc comparisons
multi comparisons not specified in advance; procedure conducted as part of an exploratory analysis after an analysis of variance
Sheffe test
method of figuring the significance of post hoc comparisons that takes into account all possible comparisons that could be made
proportion if variance accounted for
prop of total variation of scores from the grand mean that is accounted for by the variation between the means of the groups
eta squared
name for R^2 measure of effect size for ANOVAs, aka correlation ratio
Structural model
way of understanding ANOVAs as a division of the deviation of each score from the overall mean in two parts: the variation of groups and the variation between groups
SStotal
sum of squared deviations of each score from the overall mean of all scores, ignoring score group
SSwithin
sum of squared deviations of each score from the group mean
SSbetween
sum of squared deviations of each score’s group from the GM
Correlation
association between scores on two variables
Scatter diagram
graph showing the relationship between two variables; one variable is on horizontal (x) axis and the other is on the vertical (y) axis; each score is shown as a dot
Linear correlation
relation between two variables that shows up on a scatter diagram as the dots roughly following a straight line
Curvilinear correlation
relation between two variables that shows up on a scatter diagram as dots following a systematic pattern that is not a straight line
Cross-product of z scores
result of multiplying a person’s z score on one variable by the person’s z score on another variable
correlation coefficient (r)
measure of degree of linear correlation between two variables ranging from -1 to 1
direction of causality
path of causal effect; X is thought to cause Y + X to Y; Y is thought to cause X = Y to X
Correlation research design
any research design other than a true experiment
proportionate reduction in error (r^2)
measure of association between variables that is used when comparing association; aka variance accounted for
restriction in range
situation in which you figure a correlation but only a limited range of the possible values on one of the variables in included in the group studied
outliers
scores with an extreme value in relation to the other scores in the distribution
Spearman’s rule
the equivalent of a correlation coefficient for rank-related scores
Correlation matrix
common way of reporting correlation coefficients among several variables in a research article
Predictor variable (usually X)
in prediction, variable that is used to predict scores of individuals on another variable
Criterion variable (usually Y)
in prediction, a variable that is predicted
linear prediction rule
formula for making predictions; formula for prediction a criterion variables based on a person’s predictor variables (y=a+bx)
regression constant (a)
in a linear prediction rule, particular fixed number added into the prediction
regression coefficient (b)
number multiplied by a person’s score on a predictor variable as part of a linear prediction rule
regression line
line on a graph such as a scatter diagram showing the predicted value of the criterion variable for each value of the predictor variable; visual display of the linear prediction rule
slope
steepness of the angle of a regression line in a graph of the relation of scores on a predictor variable and predicted scores of a criterion variable
intercept
point where the regression line crosses the vertical axis; the regression constant (a)
error
in prediction, the difference between a person’s predicted score on the criterion variable and the person’s actual score on the criterion variable
sum of the squared erros
sum of the squared differences between each predicted score and actual score on the criterion variable
standardized regression coefficient (B)
regression coefficient in standard deviation units; shows predicted amount of change in standard deviation of the criterion variable if the value of the predictor variable increases by 1 standard deviation
bivariate prediction
prediction of scores on one variable based on scores of one another variable; aka bivariate regression
multiple correlation
correlation of a criterion variable with two or more predictor varaibles
multiple regression
procedure for predicting scores on a criterion variable from scores on two or more predictor variables
multiple correlation coefficient (R)
in multiple regression, the correlation between the criterion variable and all the predictor variables taken together
SSerror (sum of the squared errors)
sum of the squared differences between each score on the criterion variable and its predicted score
total squared error when predicting from the mean (SStotal)
sum of squared differences of each score on the criterion variable from the predicted score when predicting from the mean
