quiz 3: research designs

A researcher wants to make sure that her assistants did not give any hints regarding which participants are in which treatment groups and to also make sure the participants did not know which group they were in. She should use (a):

double-blind procedure

The value of random assignment is that it:

ensures the equivalence of the experimental and control groups

The independent variable in an experiment is defined as the:

factor that the experimenter manipulates

A positive correlation between two variables suggests that

high scores on one variable relate to high scores on the second variable.

In an experiment testing the effect of caffeine on alertness in students with attention deficit disorder, the caffeine is the

independent variable

Operational definitions are encouraged in research in order to:

make terms used in a study as explicit as possible

In an experiment on the effects of light on reading speed, which of the following is the dependent variable?

the measured reading speed

One reason for using random assignment is:

to help ensure that participant characteristics don't become confounding variables

Which of the following is the major problem involved in conducting a correlational study?

Cause-and-effect conclusions cannot be drawn.

in correlational research, the strength of the relation between two variables is indicated by:

a mathematical score ranging from +1.0 to -1.0.

An article headline claimed that "Drugs Cause Homelessness" due to a positive relationship found between homeless populations and drug use. Educated psychologists thought this might be flawed, because they thought unemployment was influencing both drug use and homelessness. This is an example of:

a third variable

The mathematical score that indicates how much two attributes are related to each other is called the

correlation coefficient