Causality and Experimental Design Concepts

The video tutorial discusses the pre-test post-test non-equivalent group design, a type of cosi experimental design. It explains the concept of non-equivalent groups due to the absence of random assignment, which affects the ability to establish causality. The tutorial describes the process of conducting pre-tests and post-tests, analyzing results for significant differences, and the implications of these differences. It also highlights the limitations of this design, particularly the threats to internal validity due to uncontrolled variables.

What is a key characteristic of the pre-test post-test non-equivalent group design?

• It involves random assignment.

• It is a type of true experimental design.

• It always results in equivalent groups.

• It lacks random assignment.

Why is random assignment important in experimental designs?

• It ensures groups are non-equivalent.

• It helps in making groups equivalent.

• It eliminates the need for a control group.

• It always results in significant differences.

Why are the groups in this design considered non-equivalent?

• Because they are always equal in size.

• Because they are pre-existing and not randomly assigned.

• Because they are always different in gender.

• Because they are randomly assigned.

What is the main challenge in establishing causality in this design?

• The groups are too small.

• The groups are not randomly assigned.

• The groups are too diverse.

• The groups are always equivalent.

In the pre-test post-test design, what is the purpose of the pre-test?

• To ensure the groups are different.

• To eliminate the need for a control group.

• To compare the groups for significant differences.

• To introduce the independent variable.

What does a significant difference in post-test scores suggest?

• The treatment was ineffective.

• The pre-test was unnecessary.

• The groups were equivalent.

• The treatment was effective.

If there is no significant difference in pre-test scores, what can be inferred?

• The groups are equivalent on the measured variable.

• The groups are equivalent on all variables.

• The groups are different on all variables.

• The treatment is ineffective.

What limitation does the pre-test post-test design have regarding other variables?

• It controls all other variables.

• It does not control other potential variables.

• It measures all variables.

• It eliminates all threats to validity.

What is a threat to internal validity in this design?

• Equivalent groups.

• Controlled variables.

• Uncontrolled variables.

• Random assignment.

What does it mean if both groups perform equally on the post-test?

• The treatment was effective.

• The groups were not equivalent.

• The pre-test was flawed.

• The treatment had no effect.