2multivar

Question 1

Longitudinal design

Answer 1

A study in which the same variables are measured in the same people at different points in time. E.g., Eron and colleagues’ (1972): Measured children children s aggression and interest in violent ’s aggression and interest in violent television programs in the same group of people across time-10 years apart

Question 2

Cross-sectional correlations:

Answer 2

: In a longitudinal design, a correlation between two variables that are measured at the same time. (like those taken at the beginning at of the study, then at the end)

Question 3

Autocorrelation:

Answer 3

The correlation of one variable with itself, measured at two different times.

Question 4

Cross-lag correlations:

Answer 4

i.e. TvViolence2001 w/ Aggression2011In a longitudinal design, a correlation between an earlier measure of one variable and a later measure of another variable. Addresses the directionality problem and help establish temporal precedence

Question 5

Longitudinal Design and 3 Prereqs for Causation

Answer 5

Covariance: Significant relationships in longitudinal designs help establish covariance.  Temporal precedence: A longitudinal design can help researchers make inferences about temporal precedence.  Wh en one cross-lag correlation is stronger, this helps todetermine which variable comes first. Internal validity: When conducted simply longitudinal studies do not help us rule out third variables.

Question 6

Longitudinal Designs: How structure so that can find causation

Answer 6

Careful researchers may g be able to design their studies or conduct the subsequent analyses in ways that address some third variables. E.g., Eron and his colleagues studied boys and girls separately; they found that a preference for violent TV predicts aggression for boys but not for girls. Rules out gender as a third variable; gender moderates the effects of TV preference on violence.

Question 7

Why not just do an experiment (instead of a longitudinal study)?

Answer 7

.Exp best way to confirm/disconfirm causal claims.But, many cases ppl can’t be randomly assigned or it would be unethical.So longitudinal design becomes a good option

Question 8

 Multiple regression (or multivariate regression):

Answer 8

A statistical technique used to test for the influence of third variables.-rule out third variables and address questions of internal validity-ex: more recess and less behavior problems-possible third variables: class size, private schools, income, etc

Question 9

Criterion Variable

Answer 9

The variable in a multiple regression that the researchers are most interested in understanding or predicting.  May also be called the dependent variable.

Question 10

Predictor Variable

Answer 10

Predictor variable: A variable in an analysis using multiple regression that is used to explain variance in the dependent or criterion vari bl ae. May also be called the independent variable.

Question 11

Beta?

Answer 11

positive B indicates positive relationship btw specific predictor variable and DV, when other variables are statistically controlled forneg B indicates neg relationship two variables when other predictors are statistically controlled for-betas change depending on what other predictor variables are being used and controlled for in the regression-can compare two Bs within same table to each other-little b shows similar associations but cannot be compared with same table to each other

Question 12

Mediating variable (or mediator):

Answer 12

A->B(med var)->CA variable that helps explain the relationship between two other variables.Can be investigated with experiments, but mediation analyses often rely on multivariate tools such as regression analyses.mediating step between the IV and DV that causes the DV-overall relationship “c” only due to relationship “a” btw IV and mediator and relationship “b” btw mediator and DV-ex: availability of recess and behavior problems, mediator = physical activity

Question 13

Statistical Significane of Beta

Answer 13

column labeled “sig” or “p”-tell whether each beta is statistically significantly different from zero-when B is zero, shows that the relationship is explained by another variable

Question 14

mediator vs moderator

Answer 14

med: “why are these two variables linked?”mod: “are these two variables linked the same way for everyone, or in every situation?”

Question 15

Third-Variable Problem

Answer 15

internal validity rule, when you can come up with an alternative explanation for the association between two variables, that alternative explanation is the third variable