Exam 6: Independent Groups Designs

An instructor randomly assigns two sections of his course to an experimental condition (new teaching method)or control condition (regular teaching method).Students in the 9:30 section receive the experimental treatment and students in the 1:30 section participate in the control condition.At the end of the semester the instructor's tests reveal that students in the 9:30 section had significantly higher test scores than students in the 1:30 section.Based on this summary,we can state that

When the findings of experiments testing the effectiveness and safety of drugs on animals are replicated in clinical trials with people,the original findings of the animal research are shown to have

A researcher tested whether exposure to images of very thin fashion models causes young women to be dissatisfied with their own body,compared to exposure to athletic body images or neutral (non-body)images.She randomly assigned 120 women from an introductory psychology course to one of three exposure conditions: very thin female images,athletic female images,or neutral images (e.g.,household objects).Each condition had 10 images,projected individually on a large screen.The young women participated in small groups.Each image was displayed for 1 minute,for a total of 10 minutes of exposure.After viewing each image,participants wrote for 30 seconds a description of the image (the participants were led to believe their memory was being tested).After viewing the images,the women completed a questionnaire about satisfaction with their body.Negative scores indicate body dissatisfaction and positive scores indicate satisfaction with their body.The mean scores for each condition were as follows: Someone unfamiliar with research methods criticizes the findings by arguing that women who viewed the very thin images probably were more dissatisfied with their bodies even before participating in the experiment.State whether you agree or disagree with this argument and explain your reasoning.

A researcher interested in young girls' exposure to thin images of Barbie dolls compared to normal-weight images ("Emme" doll)wanted to make sure girls in the two conditions (Barbie,Emme)did not differ in the number of Barbie dolls they own at home.The best way to do this would be to

A researcher was interested in whether divorce and remarriage influence the extent to which children are sociable.At a nearby school,the researcher classified 5^th-graders into one of three groups: intact parents (no divorce),divorced (single-parent families),and remarried parents.The researcher interviewed the 5^th-graders and rated their sociability,and also asked them to complete a questionnaire that assessed their level of comfort in different social situations. What type of experimental design did this researcher use?

The three steps of data analysis are

A researcher was interested in whether divorce and remarriage influence the extent to which children are sociable.At a nearby school,the researcher classified 5^th-graders into one of three groups: intact parents (no divorce),divorced (single-parent families),and remarried parents.The researcher interviewed the 5^th-graders and rated their sociability,and also asked them to complete a questionnaire that assessed their level of comfort in different social situations. Describe the independent variable in this study.

A cognitive psychologist wants to do an experiment to test a variable that may influence the memory of elderly people.She has the following constraints: only 12 people are available as possible participants,and the independent variable she plans to manipulate requires the use of a separate group for each of the two conditions.The psychologist has a reliable and valid pretest she can use to evaluate participants' memory prior to the manipulation.Which design is this psychologist likely to use?

A researcher has manipulated only one independent variable at two levels,has held constant as many other variables as possible and has balanced individual differences by using random assignment.The researcher is likely to be able to claim that the independent variable caused the observed changes in the dependent variable because the experiment is

The procedure for using block randomization in an independent groups experiment with three conditions (A,B,C)and 60 subjects is to

Which of the following is the best way to determine whether the differences in means obtained in an experiment are reliable?

A Type I error occurs when the null hypothesis is really true and we claim

Two statistical methods that researchers use to determine whether an independent variable has a reliable effect on a dependent variable are