Exam 12: Experiments With More Than One Independent Variable

Dr.Green is interested in conducting a 2 × 2 × 3 within-group factorial design, with 20 participants in each cell.How many participants does she need overall?

Dr.Gavin is conducting a 2 × 4 independent-groups factorial design.Assuming he wants 25 people in each cell, how many participants does Dr.Gavin need to recruit?

According to the textbook, why is it important to study interactions?

Studies with one independent variable can show:

RESEARCH STUDY 12.3: To study the effects of physical discomfort on attention, Dr.Lopez conducted the following study: A group of participants were required to keep one hand submerged in cold water (52 degrees).Half of the participants kept their hand in the water for 2 minutes, and half of the participants kept their hand in the water for 4 minutes.In addition, half of the participants were given a placebo pill and told it would reduce the pain of the water (pain relief assumed).The other half were given a placebo pill and told that it would have no effect (no pain relief assumed).While their hands were in the water, participants were asked to watch a video where a ball is quickly passed between and underneath three cups.At the end of the video, participants were asked to indicate under which cup the ball could be found.Whether or not the participant picked the correct cup was recorded (as a measure of whether they were paying attention).The results are below. Using factorial notation, describe Dr.Lopez's study.Given this information, how many main effects and interactions will Dr.Lopez need to examine?

Dr.Gavin decides that instead of conducting a 2 × 4 independent-groups factorial design, he is going to conduct a 2 × 4 within-groups factorial design.Which of the following things will change?

State the three types of factorial designs.

Dr.Gavin is conducting a 2 × 4 independent-groups factorial design.How many interactions will Dr.Gavin need to examine?

Neely is examining the graph of an interaction and sees that one line is flat and one line rises sharply to the right.Which of the following should Neely conclude?

In popular media articles, why does the inclusion of participant variable information often denote a factorial design?

Imagine that you read the following passage in a popular magazine.Should you conclude that the original article found evidence of an interaction? Why is or isn't there evidence of an interaction? "One study had participants watch a crime show.Half the participants watched a documentary of a murder that took place in rural Virginia, while the other half watched a movie adaptation of the same murder.The effect of viewing a crime show on people's fear of being a victim of crime depends on the participants' sex, with women in general being more fearful regardless of which show they saw, whereas men reported more fear after watching the documentary."

Imagine that you are reading a journal article and you see the following sentence: "The study used a 2 × 2 × 4 design." Where are you likely to have encountered this sentence?

The phrase "especially for" would be used to describe which of the following results?

The mathematical way to describe an interaction is:

RESEARCH STUDY 12.1: Dr.Elder was interested in the way people recognize objects as members of categories.For example, what makes us recognize a dog as being a dog and not a cat? More specifically, he was curious as to whether people think about categories in a more complex way if they contemplate an "opposite" category first.For example, does a person think differently about the category of "southern" if they first think about the category of "northern"? He is also curious as to whether people categorize differently if they are exposed to category members compared with generating category members.Dr.Elder has four groups of participants (with 30 people in each group).In Group A, participants were told to cut out pictures of dogs and cats from magazines.In Group B, participants were told to cut out pictures of just dogs from magazines.In Group C, participants were told to draw pictures of cats and dogs.In Group D, participants were told to draw pictures of just dogs.After doing this for 30 minutes, participants in all groups were asked to list the attributes that define the "dog" category.Having a higher number of attributes listed was considered to be an indication of thinking about the category in a more complex way.The results of his study are below. In graphing the difference between the differences, which of the following values would Dr.Elder use?

What are the two main reasons to conduct a factorial study?

What is the difference between a main effect and an overall effect?

Dr.Green is interested in conducting a 2 × 2 × 3 mixed factorial design, with 20 participants in each cell.Which of the following would NOT be a possible number of participants for this study?

RESEARCH STUDY 12.3: To study the effects of physical discomfort on attention, Dr.Lopez conducted the following study: A group of participants were required to keep one hand submerged in cold water (52 degrees).Half of the participants kept their hand in the water for 2 minutes, and half of the participants kept their hand in the water for 4 minutes.In addition, half of the participants were given a placebo pill and told it would reduce the pain of the water (pain relief assumed).The other half were given a placebo pill and told that it would have no effect (no pain relief assumed).While their hands were in the water, participants were asked to watch a video where a ball is quickly passed between and underneath three cups.At the end of the video, participants were asked to indicate under which cup the ball could be found.Whether or not the participant picked the correct cup was recorded (as a measure of whether they were paying attention).The results are below. Name the independent variables in this study and describe their levels.

Which of the following CANNOT be said of the interaction in a study?