Exam 6: Independent Groups Designs

Briefly outline the steps involved in order to make an inference about the effect of an independent variable using null hypothesis significance testing;be sure to indicate the conditions in which an independent variable is judged to be nonsignificant and when it is statistically significant.

When the results on an experiment are likely to be replicated if the procedures are repeated,we are more confident the findings are not due to chance factors.When this occurs we state our findings are

We can be confident that the population means differ for two conditions of an experiment when the confidence intervals for the two sample means

Figure: 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 60 women from an introductory psychology course to one of three exposure conditions: very thin female body images,athletic female images,or neutral images.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: -The alternative explanation that extraneous variables produced the different body satisfaction scores is ruled out because the researcher

After checking the data for errors and outliers,the next step in analyzing the data from a research study is to use

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

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 higher test scores than students in the 1:30 section,based on a test of statistical significance.Based on this summary,we can state that

The nonsystematic variation due to differences among subjects within each group is called

Figure: 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 60 women from an introductory psychology course to one of three exposure conditions: very thin female body images,athletic female images,or neutral images.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: -The use of very thin images and neutral images in this study represents

When researchers use the multimethod approach they can reach comparable conclusions about a research question after using different methods to study it.Our confidence in these conclusions increases and the conclusions are said to have

One major purpose of conducting experiments is to decide whether a treatment or program effectively changes behavior.The second major purpose for doing experiments is to provide

Clearly and concisely describe how a researcher could minimize the likelihood of selective subject loss in an experiment--be sure to include in your answer any risks that the researcher would be taking in trying to prevent the selective loss.

Placebo control groups and double-blind procedures are typically used to control for

Our ability to draw appropriate conclusions based on the results of an experiment depends most of all on the

The goal of a random groups design experiment is to establish the independent variable as the cause of a differences in the dependent variable.The logic of accomplishing this involves

A researcher was interested in whether divorce and remarriage influence the extent to which children are sociable. At a nearby school, the researcher classified 5th-graders into one of three groups: intact parents (no divorce), divorced (single-parent families), and remarried parents. The researcher interviewed the 5th-graders and rated their sociability, and also asked them to complete a questionnaire that assessed their level of comfort of different social situations. -Suppose that the researcher finds that the 5^th graders in the divorce (single-parent)group are less sociable than are 5^th graders in the intact and remarried groups.The researcher concludes that divorce and living in a single-parent home causes children to be less sociable,and that remarriage causes improvements in sociability.Do you accept this researcher's conclusions? Why or why not?

Describe how partial replications can be used to establish both experimental reliability and the external validity of research findings.

In a study that investigates the effects of two different doses of a drug on memory performance,the drug doses represent the ____ variable and memory performance represents the ____ variable.

Describe briefly how confidence intervals can be used to determine if the means for the two conditions of an experiment differ.

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