Psychology – Practice quiz part 2

Randomly selecting participants for a between subject experiment WONT prevent participant characteristics from becoming confounding variables. But what will?

1-holding the participant characteristic constant
2- Randomly assigning participants to treatment conditions
-3 Matching the groups with respect to the participant characteristic

A limitation of using matching rather than random assignment to form groups in a between-subjects experiment is that

matching requires another measurement procedure

Standardizing procedures across treatment conditions

minimizes variance within treatments.

When comparing means in a two-group design, which statistical analysis is most appropriate?

independent-measures t test

What is an independent-measures t test?

…

Which of the following research designs involves measuring the same group of participants in two different treatment conditions?

within-subjects

individual differences are not a problem in a within-subjects design because

individual differences are not a problem in a within-subjects design.

In a within-subjects research study, factors that change over time, such as history and maturation, can be threats to

internal validity.

In a within-subjects design, the term “participant attrition” refers to the possibility that

some of the individuals in the study may leave without completing all of the treatment conditions.

When one treatment condition has a lasting effect on the participants and influences their scores in later treatments, the study is confounded by

carryover effects.

What are carryover effects?

…

_____ the time period between treatment conditions reduces the chances of history influencing the results of a within-subjects experiment.

Shortening

Order effects can become a confounding variable because

treatment conditions at the end of the series are affected differently than conditions at the beginning.

What is the difference between carryover effects and order effects?

…

Counterbalancing is used in

within-subjects designs to distribute order effects evenly across the treatment conditions.

Name an advantage of using a between-subjects design instead of a within-subjects desing

It eliminates the risk of order effects.

In a factorial experiment, the number of factors is the number of ___________ variables.

independent

Counterbalancing is used in

within-subjects designs to distribute order effects evenly across the treatment conditions.

within-subjects experimental design

research design that compares two or more different treatment conditions (or a treatment and a control) by observing or measuring the same group of individuals in all of the treatment conditions being compared

history

environmental events other than the treatment that can change over time and may affect the scores in one treatment differently than in another treatment; threat to internal validity

maturation

any systematic changes in a participants physiology or psychology that occur during a research study and affect the participants’ scores; threat to internal validity

instrumental bias

changes in a measuring instrument that occur over time

regression toward the mean

the tendency for extreme scores on any measurement to move toward the mean when the measurement procedure is repeated; threat to internal validity

order effects

effects that occur when the experience of being tested in one treatment condition has an influence on the participants’ scores in later treatment conditions

carry-over effects

effects that occur when one treatment condition produces a change in the participants that affects their scores in subsequent treatment conditions

progressive error

changes in a participant’s behavior or performance that are related to general experience in a research study but not related to a specific treatment or treatments (practice effects, fatigue)

counterbalancing

in a within-subjects design, changing the order in which treatment conditions are administered from one participant to another so that the treatment conditions are matched with respect to time

complete counterbalancing

in within-subjects designs, using a separate group of participants for every possible order of the treatment conditions; with ‘n’ different treatment conditions, there are n! (n factorial) different orders

partial counterbalancing

using enough different orderings to make sure that each treatment condition occurs first in the sequence for one group and second for the next, third for the next, etc.

matched-subjects design

design where each individual in one group is matched with a participant in each of the other groups

1,3

a researcher is conducting an experiment comparing three treatment conditions. if the researcher uses a between-subjects design, there will be ____ score(s) for each participant but if a within-subjects design is used there will be ___ score(s) for each participant

history effects

when an outside event occurs during a within-subjects study and influences some of the treatment conditions but not others, the results are confounded by

instrumentation

a researcher evaluates the effectiveness of an art class by having an art expert judge the quality of students’ paintings at the beginning of the class, in the middle of the class, and at the end of the class. if the expert’s standards for judgement change during the class, then the internal validity of the study is threatened by _____

to use complete counterbalancing

if a researcher has a reason to expect large and long-lasting order effects, the best strategy is

within-subject designs to distribute order effects evenly across the treatment conditions

counterbalancing is used in

6

how many groups of participants would be needed to completely counterbalance a within-subjects experiment with three treatment conditions?

individual differences are not a problem with within-subjects

in within-subjects design, individual differences are a problem because

small, large

a within-subjects design has a definite advantage over a between-subjects design when the number of available subjects is relatively ____ and individual differences are relatively ____

the matched-subjects design uses a different group of participants for each treatment condition

what differentiates a matched-subjects design from a within-subjects design?

repeated-measures t test

the appropriate hypothesis test for a within-subjects design that compares two treatment conditions is

it is more likely to reveal the full relationship between the independent and dependent variable

an advantage of a multiple-treatment within-subjects design compared to a two-treatment design is