# Shared Flashcard Set

## Details

Marks Stats Final
Stats final for my co-glorious cohort and I
67
Psychology
12/04/2012

Term
 Correlation definition
Definition
 measurement of the relationship or association between variables
Term
 correlation: levels of measurement
Definition
 2 continuous or 1 continuous, 1 dichotomous categorical; MUST be equal interval
Term
 correlation: research question
Definition
 do individuals who have a low/high score on 1 variable also have a corresponding low/high score on another variable? for each unit change in X, is there a corresponding unit change in Y? how strong is the relationship between these two variables?
Term
 correlation: assumptions
Definition
 normality, linearity (HIGHLY susceptible to outliers), equal interval variables, independence of observations,
Term
 correlation: 2 types
Definition
 bivariate (2 variables, measured with Pearson's product-moment correlation R, or Spearman's rho for ordinal/high outlier data) or partial (explore relationship b/t 2 variables while statistically controlling for a third)
Term
 benefits of partial correlation
Definition
 provides a more clear, accurate depiction of actual relationship between 2 variables
Term
 example of correlation write up
Definition
 Results shows a strong, positive correlation between posting stats shit on Facebook and being a total dork (r = .88, p < .01). This relationship remained significant, even after controlling for number of hours spent drooling over David Klonsky's LCA paper ( r = .66, p < .01).
Term
 correlation: measurement (2)
Definition
 strength/ magnitude (how spread are data around line of best fit? tight or loose?)direction (+ or -) low~ low, high~high, low~high, high~low
Term
 correlation coefficient
Definition
 calculated using z-scores (need z's because of different scales, with different means and SDs) cross products= zscore of x X zscore of y = avg of cross products= R
Term
 Pearson's correlation (r)
Definition
 correlation coefficient r= regression, sum of cross products of the z scores/ n = + - 1
Term
 Spearman's rho
Definition
 correlation coefficient when using ordinal data or highly skewed (lots of outlier) data
Term
 small, medium, large correlations
Definition
 .1-2.9, .3-.49, .5 and up
Term
 2 methods to test for outliers
Definition
 histogram (univariate)scatterplot (multivariate)
Term
 reliability
Definition
 consistency, stability of a measure. necessary but not sufficient for validity of the measure
Term
 validity
Definition
 degree to which an instrument measures the construct intended, accuracy
Term
 small, medium, large measure of reliability
Definition
 .45-.65 shitty.70-.80 acceptable>.80 optimal.99= measuring same thing? context needed
Term
 frequency scales
Definition
 Likert, how often behavior or event has occured, opinion as to how strong a person feels about something. Assume linear relationship. neutral point? can use as interval data to use parametric tests. need normality of distribution for certain tests.
Term
 Thurstone scales
Definition
 empirical data from judges to ensure attitudes/behaviors being measured are spaced along continuum of equal rating
Term
 guttman scaling
Definition
 hierarchical scaling technique that ranks items such that individuals who agree with higher ranked item will also agree with items of lower rank
Term
 piloting a measure
Definition
 should be done w a smaller sample, but large enough to allow for a cronbach's alpha greater than .70, determine which items should be kept/deleted
Term
 factor analysis
Definition
 extraction, principal component analysis, varimax/oblimination rotation
Term
 PCA
Definition
 principal component analysis- explores relationship between variables, provides basis for removal of uncessary items and ID subscales/domains
Term
 varimax/oblimin rotation
Definition
 factor rotation that maximized loadings of variables on different subscales. varimax with correlated. Oblimin with uncorrelated. ID number of domains in measure
Term
 construct validity
Definition
 degree to which an instrument is related to operationally defined theory and concepts
Term
 construct validity:measurements
Definition
 contrasted groups- 2 groups high and low known, means should differhypothesis testing- theoreticalfactor analysis- related items kept, exploratory and confirmatory
Term
 convergent/discriminant validity: measurements
Definition
 multitrait- multimethod approach- MTMM 2 more constructs with 2 more methods, correlation matrix for relationships between traits
Term
 translational validity
Definition
 face and content validity-
Term
 content validity
Definition
 items measure the complete range of the attribute under study (i.e. not 4 types of NSSI, but 14) determined by lit review, experts, population sampling, largest pooling then reduced with factor analysis
Term
 face validity
Definition
 instrument looks like it measures the construct of interest, subjective,
Term
 criterion validity (4 types)
Definition
 concurrent, predictive, convergent, discriminant; relationship between measurement and construct based on performance on another variable
Term
 concurrent validity
Definition
 scores on a measure correlated to a related criterion at the same point in time
Term
 concurrent validity: measurements
Definition
 exploratory factor analysis, eigen >1; confirmatory factor analysis, loading on each subscale >,4; principal components analysis ( 5 pps per variable) ex. ISAS and SITBI
Term
 predictive validity
Definition
 degree to which scores predict performance on some future criterion
Term
 predictive validity: measurements
Definition
 correlations, regressionsex. ISAS behavioral forecast predicts NSSI
Term
 convergent validity
Definition
 correspondence between constructs that are theoretically similar.
Term
 convergent validity: measurements
Definition
 correlations. ex ISAS and MSI-BPD
Term
 discriminant validity
Definition
 measurement differentiates between constructs that are theoretically different
Term
 discriminant validity: measurements
Definition
 MT-MTT, weak/no correlation. ex ISAS and SITBI gesture, suicide attempt
Term
 content validity: measurements
Definition
 content validity ration (CVR) or content validity intex (CVI) depend on number of experts (+7)
Term
 test-retest reliability
Definition
 similar scores at different times, 2 weeks-1 month, not due to chance, some states do change, so not useful
Term
 internal consistency
Definition
 cronbach's alpha. inter-item correlations to determine if items measure some construct. how well they "hang" together. can add items to increase. if over .9 might be measuring same thing
Term
 parralel/ alternate forms of reliability
Definition
 different items pool to test same concepts, ie day and night measure.
Term
 Magnusson quote as to why we need good measures
Definition
 "models are never more accurate, reliable, or valid than the measures you put into them"
Term
 regression definition
Definition
 use correlations in a systematic/meaningful way to test hypotheses. predict/ calculate any value of y (DV) from a value of x (IV). based on probabilities
Term
 variance in regression
Definition
 R squared multiple correlation. how much of DV's variance is accounted for by the IV. 0-1. always positive. closer to 1= greater amount of variance explained. tests magnitude of prediction and mediation.
Term
 y= Bo + B1 (x) + err
Definition
 y= DVBo= intercept, constant B1= slope/ beta weight/ regression weightX= value of IVerr= random, unsystematic errorUSE UNSTANDARDIZED SCORES
Term
 assumptions of regressions
Definition
 linearity/normality, independence and homogeneity of error, heteroscedasticity- variability at one point is similar to variability at different point.
Term
 uni vs multi regressions
Definition
 predict DV from IV OR >1 IV from 1 DV (mediation)
Term
 leverage
Definition
 how far case is from other cases
Term
 discrepancy
Definition
 how in line with linear trend
Term
 regressions standardized coefficients
Definition
 interpreted as correlation strength, direction, significance.
Term
 collinearity
Definition
 measures are overly related, may be measuring same thing. everything is significant when testing reliablity
Term
 variable centered approach
Definition
 given prior behavior, scores, genetic markers, contextual risk and protective factors, individuals are interchangeable units who apart from random error, do not differ qualitatively or quantitatively from each other.
Term
 person centered approach
Definition
 how individuals change or behave. how individuals function, holistic. do not assume normality, less sensitive than parametric tests and may fail to detect differences that actually exist (type I error)
Term
 synchronization
Definition
 developmental processes are active, integrated, complex, dynamic, adaptive in relation to greater system
Term
 ecological fallacy
Definition
 drawing false conclusions about individual behavior from population behavior
Term
 atomistic fallacy
Definition
 drawing false conclusions about aggregate behavior from individuals
Term
 types of person centered analyses
Definition
 classification (cluster and LCA)hybrid classification (growth mix model)single-subject methods (dynamic factor analysis)variable oriented methods: latent growth curve modeling
Term
 cluster analysis
Definition
 examine how groups of individuals are similar to one another, and different from individuals in other groups/clusters. exploratory in nature
Term
 hierarchical cluster analysis
Definition
 small >50 data sets standardized continuous data
Term
 K-means cluster analysis
Definition
 moderate sample size, standardized continuous data, assign cluster then recheck means to maximize differences b/t groups. may or may not ask SPSS to create a specific number of groups
Term
 2 step cluster analysis
Definition
 large data sets, computer selects number of clusters based on most relevant variables, maximize differences bt clusters, can use continuous, discrete nominal data. step 1= preclustering put new in with preclusters or make a new one.step 2= use hierarchical techniques to make two clusters then assign to clusters
Term
 BIC
Definition
 Shwarz's Bayesian ID criterion; change of more than one= best number of clustersexactly how much more likely it is to get an individual from group a vs group b
Term
 2 ways of clustering
Definition
 log likelihood estimates (MLE or LSE) with mix of variable typesEuclidian distance same standardized variables
Term
 latent class analysis
Definition
 ID unique classes of cases like cluster analysis with categorical data. estimation uses MLE. assumes variables are uncorrelated within classes, although often not the case
Term
 latent variable analysis
Definition
 determine latent variables (ones that cannot be measured directly)- circles based on observed/ indicator variables- boxes. need 4
Term
 example of regression write up
Definition
 Time spent oogling over David Klonsky's LCA is predictive of desire to TA stats for smelly undergrads, such that more time spent oogling was significantly positively associated with desire to TA smelly undergrads (r = .66, p < .01). Time spent oogling explained 80% of the variance in desire to TA smelly undergrads.
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