Exam 11: Factorial Designs

A doctor suspects that the effectiveness of a new cholesterol medication depends on the age of the patient. If the doctor is correct, the results from a two-factor study comparing medication versus no-medication for young versus old patients should produce an interaction.

A two-factor study compares three different treatment conditions (factor 1) for males and females (factor 2). In this study, the main effect for gender is determined by comparing the overall mean score for the males (averaged over the three treatments) and the corresponding overall mean score for the females (averaged over the three treatments).

How can variance be reduced in a between-subjects design?

What is the primary disadvantage of adding factors to investigate a four-way interaction?

The following data represent the means for each treatment condition in a two-factor experiment. What pattern of results is shown in the data? B1 B2 =30 =30 =40 =10

In a two-factor experiment with two levels of factor A and 2 levels of factor B, three of the treatment means are essentially identical and one is substantially different from the others. What result(s) would be produced by this pattern of treatment means?

The advantage of a two-factor design compared to two single-factor designs is the ability to ____.

How many separate groups of participants would be needed for a between-subjects, two-factor study with three levels of factor A and four levels of factor B?

A researcher who is examining the effects of temperature and humidity on the eating behavior of rats uses a factorial experiment comparing three different temperatures (70°, 80°, and 90°) and two humidity conditions (low and high). How many factors are in the experiment?

The following data show the means for four treatment conditions as well as the overall means for the columns and the rows. For these data, what numbers are compared to assess the main effect of factor A? 1 =20 =60 =40 2 =30 =70 =50

A researcher can replicate and expand a study by repeating the previous study in every way except adding an additional factor.

What is the relationship between main effects and interactions?

The students in one gym class receive a self-esteem program as part of their sports training. To evaluate the program, a researcher measures self-esteem for the students before and after the program and compares their scores with those from another class that did not receive the program but was measured at the same two times. What kind of design is being used?

One advantage of a factorial research design is that is creates a more realistic situation in which to observe the relationship between variables.

The following data represent the means for each treatment condition in a two-factor experiment. Note that one mean is not given. What value for the missing mean would result in NO interaction between A and B? $\quad$$\quad$$\quad$$\quad$$\text {B1 }$$\quad$$\quad$$\quad$$\text {B2 }$ A1 A2 40 60 20 40

A factorial study compares the effectiveness of two allergy medications by measuring symptoms immediately before taking the medication, 30 minutes after the medication, and 3 hours after the medication. Half of the participants take one of the medications and the rest take the second medication. Which statement accurately describes this study?

If a researcher adds order of treatment as a factor, and finds that the means are the same whether a treatment is presented first or second, then there are no order effects present in that study.

In a factorial design, an interaction between the factors occurs whenever ____.

For a two-factor design, describe what is meant by a "main effect" and an "interaction"?

A factorial study measures allergy symptoms before and after taking medication for a group taking the real medication and a control group taking a placebo. What kind of design is being used?