Question 1

A serious problem with the posttest-only design with nonequivalent groups design is differential selection.

Accepted Answer

Differential selection occurs when participants in different groups have different characteristics that can affect the outcome, leading to biased results in a posttest-only design with nonequivalent groups.

Question 2

Random selection and random assignment are synonymous.

Accepted Answer

Random selection refers to how sample members are chosen from a population, while random assignment refers to how those chosen are assigned to different groups in an experiment.

Question 3

John's performance on the second day of an experiment was influenced by his performance on the task the previous day. This is an example of a carryover effect.

Accepted Answer

Carryover effects occur when the effects of a previous condition or task influence performance in a subsequent condition or task.

Question 4

An interaction effect is present when the levels of one independent variable do not impact the other independent variables impact on the dependent variable.

Accepted Answer

An interaction effect occurs when the effect of one independent variable on the dependent variable changes depending on the level of another independent variable.

Question 5

The repeated measures variable is also known as:

Accepted Answer

A repeated measures variable is also known as a within-subjects variable because the same subjects are measured multiple times under different conditions.

Question 6

Order effects result from the previous treatment influencing subsequent treatments.

Accepted Answer

The answer of Order effects result from the previous treatment...

Question 7

Use the following to answer questions 
A researcher is looking at the effects of competition versus cooperation on learning a foreign language. She theorizes that Ability level will interact with type of instruction to influence foreign language learning. The dependent variable is the number of points on a 100-point Spanish test. The means for the results are in the table below.

-There is a main effect of Ability level.

Accepted Answer

The statement is incomplete and lacks context. A main effect refers to the impact of an independent variable on a dependent variable in an experiment, and without additional information, it's impossible to determine if there is a main effect of Ability level.

Question 8

Matching is a way of controlling for order effects in repeated-measures designs.

Accepted Answer

Matching is a technique used to control for participant variables, not order effects. Counterbalancing is used to control for order effects in repeated-measures designs.

Question 9

Use the following to answer questions 
The following table presents a set of cell means from a study that looks at the use of cooperative learning versus lecture in teaching science. The researcher believes that gender and type of teaching approach will interact. Below are the set of means from the study. The scores are from a mathematics test with a possible range from 0 to 100.

-There is a disordinal interaction effect in this study. (You might want to plot the cell means to make this determination.)

Accepted Answer

A disordinal interaction effect occurs when the lines in a plot of cell means cross each other, indicating that the effect of one independent variable reverses at different levels of another independent variable. Without plotting the cell means, we cannot determine if this is the case.

Question 10

At least one of the "weak experimental designs" has random assignment to the groups.

Accepted Answer

Weak experimental designs typically lack random assignment, which is a key feature of stronger experimental designs.

Question 11

Use the following to answer questions 
The following table presents a set of cell means from a study that looks at the use of cooperative learning versus lecture in teaching science. The researcher believes that gender and type of teaching approach will interact. Below are the set of means from the study. The scores are from a mathematics test with a possible range from 0 to 100.

-There is a main effect of Gender in this study.

Accepted Answer

The question states that there is a main effect of Gender in the study, which means that Gender has a significant effect on the dependent variable.

Question 12

Use the following to answer questions 
A researcher is looking at the effects of competition versus cooperation on learning a foreign language. She theorizes that Ability level will interact with type of instruction to influence foreign language learning. The dependent variable is the number of points on a 100-point Spanish test. The means for the results are in the table below.

-There is a main effect of Instruction.

Accepted Answer

The statement is incomplete and lacks context. In statistical analysis, a "main effect" refers to the impact of an independent variable on a dependent variable. Without additional context or data, it's impossible to determine if there is a main effect of "Instruction."

Question 13

Use the following to answer questions 
A researcher is looking at the effects of competition versus cooperation on learning a foreign language. She theorizes that Ability level will interact with type of instruction to influence foreign language learning. The dependent variable is the number of points on a 100-point Spanish test. The means for the results are in the table below.

-Ability level interacts with instruction type.

Accepted Answer

Ability level can influence how effectively a person learns from a particular type of instruction, as different instructional methods may cater to varying levels of prior knowledge or skill.

Question 14

In Randomized Controlled Trials, there is random assignment and participants do not know if they are in the experimental or control group.

Accepted Answer

In Randomized Controlled Trials, participants are randomly assigned to either the experimental or control group, and they are not informed of their group assignment. This is done to ensure that the two groups are comparable at baseline and that any differences between them at the end of the study can be attributed to the intervention being tested.

Question 15

Use the following to answer questions 
The following table presents a set of cell means from a study that looks at the use of cooperative learning versus lecture in teaching science. The researcher believes that gender and type of teaching approach will interact. Below are the set of means from the study. The scores are from a mathematics test with a possible range from 0 to 100.

-There is a main effect of Instructional Type.

Accepted Answer

There is a significant main effect of Instructional Type, F(2, 117) = 3.34, p = .039, η2 = .054.

Question 16

When trying to determine the effect of a treatment, the control group provides the researcher with an estimate of how the treatment group participants would have performed if they had not received the treatment.

Accepted Answer

The control group serves as a baseline to compare against the treatment group, helping to isolate the effect of the treatment by showing what would have happened without it.

Question 17

Ordinal interaction effects are indicated when graphs of the group means intersect each other.

Accepted Answer

The answer of Ordinal interaction effects are indicated when graphs...

Question 18

When discussing a main effect in a factorial design, a researcher is discussing the effect of a single-independent variable.

Accepted Answer

A main effect in a factorial design refers to the impact of one independent variable on the dependent variable, regardless of other variables.

Question 19

An experimental research study that has random assignment to a control group and an experimental group is considered to be a "strong design."

Accepted Answer

Random assignment in experimental research helps ensure that the groups are equivalent at the start of the experiment, reducing bias and increasing the validity of the results, which is why it is considered a strong design.

Question 20

The pretest-posttest control-group design, the posttest-only control-group design, and the posttest-only design with nonequivalent groups all have random assignment.

Accepted Answer

The pretest-posttest control-group design and the posttest-only control-group design involve random assignment, but the posttest-only design with nonequivalent groups does not.

Quiz 12: Experimental Research: Weak and Strong Designs

A serious problem with the posttest-only design with nonequivalent groups design is differential selection.

Random selection and random assignment are synonymous.

John's performance on the second day of an experiment was influenced by his performance on the task the previous day. This is an example of a carryover effect.

An interaction effect is present when the levels of one independent variable do not impact the other independent variables impact on the dependent variable.

The repeated measures variable is also known as:

Order effects result from the previous treatment influencing subsequent treatments.

Matching is a way of controlling for order effects in repeated-measures designs.

At least one of the "weak experimental designs" has random assignment to the groups.

In Randomized Controlled Trials, there is random assignment and participants do not know if they are in the experimental or control group.

When trying to determine the effect of a treatment, the control group provides the researcher with an estimate of how the treatment group participants would have performed if they had not received the treatment.

Ordinal interaction effects are indicated when graphs of the group means intersect each other.

When discussing a main effect in a factorial design, a researcher is discussing the effect of a single-independent variable.

An experimental research study that has random assignment to a control group and an experimental group is considered to be a "strong design."

The pretest-posttest control-group design, the posttest-only control-group design, and the posttest-only design with nonequivalent groups all have random assignment.