Exam 10: The Nonexperimental and Quasi-Experimental Strategies: Nonequivalent Group,Pre–Post,and Developmental Designs.

Describe the similarities and differences between experiments and nonexperiments or quasi-experiments.

A researcher introduces a new mathematics program in one school district and uses a neighboring district as a no-treatment control group.After the program is in place for six months,the researcher intends to give the students in both districts a standardized mathematics test and then compare their scores.This research cannot be classified as a true experiment because ____.

Nonexperimental research typically involves looking at differences between preexisting groups or at changes that occur over time.

In a differential research design,the participant characteristic that is used to define the groups is called a(n)____ variable.

Which study illustrates a nonexperimental study?

A differential research design is an example of a ____.

A pretest-posttest design (OXO)is considered to be a(n)____.

A research study that evaluates changes in behavior related to age over time by examining one group of participants who are all roughly the same age is called a(n)____.

A researcher studies language development by selecting a sample of two-year-old children and giving them a language skill test.Each year for the next two years,the children are brought back and tested again.The researcher plans to compare the children's scores at age two,age three,and age four.This study is an example of a(n)____.

Describe the fundamental flaw that prevents a nonequivalent group design from being a true experiment.(That is,why can't these designs produce an unambiguous cause-and-effect explanation?)Explain how the pretest scores in a pretest-posttest nonequivalent control group design help reduce this problem.

In a cross-sectional developmental study,age would be the quasi-independent variable.

A repeated-measures analysis of variance is the appropriate statistical analysis for comparing mean differences for a differential design comparing samples representing three populations.

A clinical psychologist measures body satisfaction for a group of clients diagnosed with anorexia nervosa each day for one week before and for one week after the psychologist begins a series of group therapy sessions.This is an example of a(n)____ design.

What is the appropriate statistical analysis for evaluating the after treatment mean difference for a posttest only nonequivalent control group design?

A series of observations before treatment allows a researcher to determine whether ____.

A cross-sectional design comparing three different ages would require three separate groups of participants.

The concept of nonequivalent groups means that the number of participants is different from one group to another.

Describe the similarities and differences between time-series and interrupted time-series designs.

The goal of the pre-post design is to examine the effects of treatment by measuring ____.

Some threats to internal validity are related to time and other threats are related to differences between groups.What is a threat related to time?