Exam 12: Experiments With More Than One Independent Variable

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 Dr.Lopez's study as an example, explain why an interaction is often described by saying "it depends."

An author might use all of the following methods to indicate statistical significance EXCEPT:

Imagine that you read the following passage in a journal article.Provide three pieces of information that this passage tells the reader about the study conducted. "A 3 × 4 within-subjects design was specified that varied color of paper (blue, pink, white) and font size (10 point, 12 point, 14 point, 16 point).The time it took participants to read the printed word was measured."

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 the marginal means, state whether it appears that the main effects in Dr.Lopez's study are important.(You do not need to say whether the main effects are statistically significant but simply whether a difference appears to exist.)

Dr.Gavin decides that instead of conducting a 2 × 4 independent-groups factorial design, he is going to conduct a 2 × 3 × 4 mixed factorial design.Which of the following things will NOT have to change?

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. How many participant variables exist in Dr.Elder's study?

The number of main effects that need to be examined is the number of independent variables.

What does the author of the textbook mean when she writes, "We don't live in a main effect world"?

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. Which of the following could be said of the focus of activity variable in Dr.Elder's study?

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. To determine if there is a main effect for type of activity, Dr.Elder must examine how many marginal means?

If a study has a difference in the differences, you know the study definitely has a:

A "difference in the difference between the differences" would indicate which of the following?

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. Imagine that Dr.Lopez decides to manipulate the pain duration differently.He now has three levels of this variable: 2 minutes, 4 minutes, and 6 minutes.Using factorial notation, describe Dr.Lopez's study.Given this new study design, how does this change the number of cells, main effects, and interactions in Dr.Lopez's study?

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. Which of the following reasons is the most likely reason Dr.Elder conducted a factorial design?

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. Provide a graph of the possible interaction in Dr.Lopez's study and discuss whether Dr.Lopez should conclude that an interaction exists in his 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. Imagine that Dr.Lopez decides to add an additional variable to his study.He is curious as to whether the results of the study vary based on sex (male and female).The graphs of the results are below.Discuss whether Dr.Lopez should conclude that a three-way interaction exists in his study.

In the case of a factorial design, another term for independent variable is:

If a study describes the "difference in differences," what is the minimum number of variables the researchers were studying?

Dr.Gavin is conducting a 2 × 4 independent-groups factorial design.How many independent variables are in his study?

Provide two reasons a researcher would want to conduct a factorial study.