Experimental Psychology Chapter 5

Which is a critical difference between quasi-experimental and experimental designs?

experimental designs randomly assign subjects to different treatment conditions

Multiple correlation is represented by the symbol

R

Which method creates causal models by measuring relationships over time?

cross-lagged panel design

If a survey found a correlation of r = - .03 between income level and happiness, this would suggest that

there was no appreciable relationship between income level and happiness

Which quasi-experimental design would you use to compare time spent this month in chat rooms by college freshmen and seniors?

cross-sectional study

The Solomon 4-group design is an extension of the ____ design

pretest/posttest

Researchers can use ____ to predict the score on one behavior from scores on two related behaviors

multiple regression analysis

If time spent watching television and scores on a vocabulary were correlated, we could plug in a subject's viewing time and use ____ to predict vocabulary test performance

linear regression analysis

Cohen (1988) has argued that a coefficient of determination of ___ or more indicates a strong association between two variables

0.25

A shotgun approach, while not elegant, has heuristic value. This means that this strategy

helps us discover new findings

How do quasi-experiments compare with laboratory experiments?

quasi-experiments achieve lower internal validity

The ____ of a correlation coefficient indexes its strength

absolute value

Researchers measured the sugared-beverage consumption and obesity of the same children for two years. They found that when these children added one sugared drink a day to their diet, their risk of obesity increased 60%. Which quasi-experimental design did they use?

longitudinal design

Longitudinal designs can be challenging due to

extensive time commitment and subject dropout

In a cross-lagged panel design, researchers focus on the ____ to identify a possible causal path

diagonal correlations

Choose the quasi-experimental design in which subjects of different ages are measured at the same time to compare their attitudes

cross-sectional study

Which statistic would a researcher use when measuring the relationships among age, television viewing, and vocabulary?

multiple correlation

If depression increases alcohol consumption and alcohol consumption worsens depression, we could not infer a causal relationship due to the ____ problem

bidirectional causation

Casual modeling

creating and testing models that may suggest cause-and-effect relationships among behaviors

Coefficient of determination (r^2)

in a correlational study, an estimate of the amount of variability in scores on one variable that can be explained by the other variable

Correlation

the degree of relationship between two traits, behaviors, or events, represented by r

Correlational study

a study designed to determine the correlation between two traits, behaviors, or events

Cross-lagged panel design

a method in which the same set of behaviors or characteristics are measured at two separate points in time (often years apart); six different correlations are computed, and the pattern of correlations is used to infer the casual direction

Cross-sectional study

a method in which different groups of subjects who are at different stages are measured at a single point in time; a method that looks for time-related changes

Ex-post facto study

a study in which a researcher systematically examines the effects of pre-existing subjects characteristics (often called subject variables) by forming groups based on these naturally occurring differences between subjects

Linear regression analysis

a correlation-based method for estimating a score on one measured behavior from a score on the other when two behaviors are strongly related

Longitudinal design

a method in which the same group of subjects is followed and measured at different points in time; a method that looks for changes across time

Multiple correclation

statistical intercorrelations among three or more behaviors, represented by R

Multiple regression analysis

a correlation-based technique (from multiple correlation) that uses a regression equation to predict the score on one behavior from scores on the other related behaviors

Negative correlation

the relationship between two variables such that an increase in one is associated with a decrease in the other; also called an inverse relationship

Nonequivalent groups design

a design in which the researcher compares the effects of different treatment conditions on preexisting groups of participants

Partial correlation

an analysis that allows the statistical influence of one measured variable to be held constant while computing the correlation between the other two measured variables

Path analysis

an important correlation-based method in which subjects are measured on several related behaviors; the researcher creates (and tests) models of possible causal sequences using sophisticated correlation techniques

Positive correlation

the relationship between two measures such that an increase in the value of one is associated with an increase in the value of the other; also called a direct relationsip

Pretest/posttest design

a research design used to assess whether the occurrence of an event alters behavior; scores from measurements made before and after the event (called the pretest and posttest) are compared

Quasi-experimental designs

often seem like (as the prefix quasi- implies) real experiments, but they lack one or more of its essential elements, such as manipulation of antecedents and random assignment to treatment conditions

Regression line

the line of best fit; represents the equation that best describes the mathematical relationship between two variables measured in a correlational study

Scatterplot

a graph of data from a correlational study, created by plotting pairs of scores from each subject; the value of one variable is plotted on the X (horizontal) axis and the other variable on the Y (vertical) axis

Simple correlations

relationships between pairs of scores from each subject

Subject variable

the characteristics of the subjects in an experiment or quasi-experiment that cannot be manipulated by the researcher; sometimes used to select subjects into groups