Exam 10: Introduction to Simple Experiments

When interrogating the construct validity of the dependent variable in an experiment, which of the following questions should be asked?

The ability for a study to reveal a statistically significant difference between the levels of an independent variable when one truly exists is known as:

In true experiments, is to dependent variable as is to independent variable.

RESEARCH STUDY 10.1: Dr.Lonsbary is a cognitive psychologist who is curious about how mood affects memory.She recruited 60 high school students and divided them into three groups.Group A listened to a 5-minute piece of music intended to make them feel happy ("Happy" by Pharrell).Group B listened to a 5-minute piece of music intended to make them feel sad (a song titled "Home Is Such a Lonely Place" by Blink-182).Group C listened to no music and instead was asked to sit quietly for 5 minutes (thought to make them feel neutral). When a participant would come to her laboratory, Dr.Lonsbary would greet the participant and then ask him or her to roll a six-sided die.Participants who rolled a 1 or 2 were assigned to Group A.Participants who rolled a 3 or 4 were assigned to Group B.Participants who rolled a 5 or 6 were assigned to Group C.The participants were then given an unlabeled CD to listen to based on their group assignment.The CD contained either the song selection or 5 minutes of silence.They were then escorted into a different room, where they were greeted by a research assistant who conducted the experiment.The research assistant sat the participants in front of a computer screen and told them that a list of 25 words would be displayed on the screen.They were instructed to listen to the CD with headphones while trying to memorize the list of words.All participants were given the same list of 25 common words to remember (e.g., desk, gray, plane, car, mask). When 5 minutes had passed, the screen displayed a question asking them whether they felt happy, sad, or neutral.After the participant responded, a new screen was displayed asking them to type in all the words they could remember from the list of 25 words.All participants were given 3 minutes to type the words they remembered.Afterward, the participant was thanked and dismissed.In response to the mood question, a majority of Group A participants said they were happy, a majority of Group B participants said they were sad, and a majority of Group C participants said they were neutral in their mood.Dr.Lonsbary found the following results in response to the number of words remembered. Dr.Lonsbary's colleague, Dr.Chavis, recommended randomly assigning the participants to the three groups.His recommendation was designed to avoid which of the following?

Experiments use random assignment to avoid which of the following?

What is a design confound? What type of validity is threatened by design confounds, and how is it threatened? Explain why not all problems in a study are necessarily confounds.

Explain why control variables are necessary in experiments and why they are not actually variables.

RESEARCH STUDY 10.1: Dr.Lonsbary is a cognitive psychologist who is curious about how mood affects memory.She recruited 60 high school students and divided them into three groups.Group A listened to a 5-minute piece of music intended to make them feel happy ("Happy" by Pharrell).Group B listened to a 5-minute piece of music intended to make them feel sad (a song titled "Home Is Such a Lonely Place" by Blink-182).Group C listened to no music and instead was asked to sit quietly for 5 minutes (thought to make them feel neutral). When a participant would come to her laboratory, Dr.Lonsbary would greet the participant and then ask him or her to roll a six-sided die.Participants who rolled a 1 or 2 were assigned to Group A.Participants who rolled a 3 or 4 were assigned to Group B.Participants who rolled a 5 or 6 were assigned to Group C.The participants were then given an unlabeled CD to listen to based on their group assignment.The CD contained either the song selection or 5 minutes of silence.They were then escorted into a different room, where they were greeted by a research assistant who conducted the experiment.The research assistant sat the participants in front of a computer screen and told them that a list of 25 words would be displayed on the screen.They were instructed to listen to the CD with headphones while trying to memorize the list of words.All participants were given the same list of 25 common words to remember (e.g., desk, gray, plane, car, mask). When 5 minutes had passed, the screen displayed a question asking them whether they felt happy, sad, or neutral.After the participant responded, a new screen was displayed asking them to type in all the words they could remember from the list of 25 words.All participants were given 3 minutes to type the words they remembered.Afterward, the participant was thanked and dismissed.In response to the mood question, a majority of Group A participants said they were happy, a majority of Group B participants said they were sad, and a majority of Group C participants said they were neutral in their mood.Dr.Lonsbary found the following results in response to the number of words remembered. Prior to conducting the current study, Dr.Lonsbary asked her research assistant to use the same mood manipulation with a sample of 30 college students to determine if people's moods really did change after listening to the music.Running this preliminary study helps establish validity.

RESEARCH STUDY 10.1: Dr.Lonsbary is a cognitive psychologist who is curious about how mood affects memory.She recruited 60 high school students and divided them into three groups.Group A listened to a 5-minute piece of music intended to make them feel happy ("Happy" by Pharrell).Group B listened to a 5-minute piece of music intended to make them feel sad (a song titled "Home Is Such a Lonely Place" by Blink-182).Group C listened to no music and instead was asked to sit quietly for 5 minutes (thought to make them feel neutral). When a participant would come to her laboratory, Dr.Lonsbary would greet the participant and then ask him or her to roll a six-sided die.Participants who rolled a 1 or 2 were assigned to Group A.Participants who rolled a 3 or 4 were assigned to Group B.Participants who rolled a 5 or 6 were assigned to Group C.The participants were then given an unlabeled CD to listen to based on their group assignment.The CD contained either the song selection or 5 minutes of silence.They were then escorted into a different room, where they were greeted by a research assistant who conducted the experiment.The research assistant sat the participants in front of a computer screen and told them that a list of 25 words would be displayed on the screen.They were instructed to listen to the CD with headphones while trying to memorize the list of words.All participants were given the same list of 25 common words to remember (e.g., desk, gray, plane, car, mask). When 5 minutes had passed, the screen displayed a question asking them whether they felt happy, sad, or neutral.After the participant responded, a new screen was displayed asking them to type in all the words they could remember from the list of 25 words.All participants were given 3 minutes to type the words they remembered.Afterward, the participant was thanked and dismissed.In response to the mood question, a majority of Group A participants said they were happy, a majority of Group B participants said they were sad, and a majority of Group C participants said they were neutral in their mood.Dr.Lonsbary found the following results in response to the number of words remembered. Dr.Lonsbary's study asked participants to report on their mood before completing the memory test.Her decision to include this step was done to address the study's validity.

RESEARCH STUDY 10.1: Dr.Lonsbary is a cognitive psychologist who is curious about how mood affects memory.She recruited 60 high school students and divided them into three groups.Group A listened to a 5-minute piece of music intended to make them feel happy ("Happy" by Pharrell).Group B listened to a 5-minute piece of music intended to make them feel sad (a song titled "Home Is Such a Lonely Place" by Blink-182).Group C listened to no music and instead was asked to sit quietly for 5 minutes (thought to make them feel neutral). When a participant would come to her laboratory, Dr.Lonsbary would greet the participant and then ask him or her to roll a six-sided die.Participants who rolled a 1 or 2 were assigned to Group A.Participants who rolled a 3 or 4 were assigned to Group B.Participants who rolled a 5 or 6 were assigned to Group C.The participants were then given an unlabeled CD to listen to based on their group assignment.The CD contained either the song selection or 5 minutes of silence.They were then escorted into a different room, where they were greeted by a research assistant who conducted the experiment.The research assistant sat the participants in front of a computer screen and told them that a list of 25 words would be displayed on the screen.They were instructed to listen to the CD with headphones while trying to memorize the list of words.All participants were given the same list of 25 common words to remember (e.g., desk, gray, plane, car, mask). When 5 minutes had passed, the screen displayed a question asking them whether they felt happy, sad, or neutral.After the participant responded, a new screen was displayed asking them to type in all the words they could remember from the list of 25 words.All participants were given 3 minutes to type the words they remembered.Afterward, the participant was thanked and dismissed.In response to the mood question, a majority of Group A participants said they were happy, a majority of Group B participants said they were sad, and a majority of Group C participants said they were neutral in their mood.Dr.Lonsbary found the following results in response to the number of words remembered. In Dr.Lonsbary's study, which of the following is NOT present?

RESEARCH STUDY 10.1: Dr.Lonsbary is a cognitive psychologist who is curious about how mood affects memory.She recruited 60 high school students and divided them into three groups.Group A listened to a 5-minute piece of music intended to make them feel happy ("Happy" by Pharrell).Group B listened to a 5-minute piece of music intended to make them feel sad (a song titled "Home Is Such a Lonely Place" by Blink-182).Group C listened to no music and instead was asked to sit quietly for 5 minutes (thought to make them feel neutral). When a participant would come to her laboratory, Dr.Lonsbary would greet the participant and then ask him or her to roll a six-sided die.Participants who rolled a 1 or 2 were assigned to Group A.Participants who rolled a 3 or 4 were assigned to Group B.Participants who rolled a 5 or 6 were assigned to Group C.The participants were then given an unlabeled CD to listen to based on their group assignment.The CD contained either the song selection or 5 minutes of silence.They were then escorted into a different room, where they were greeted by a research assistant who conducted the experiment.The research assistant sat the participants in front of a computer screen and told them that a list of 25 words would be displayed on the screen.They were instructed to listen to the CD with headphones while trying to memorize the list of words.All participants were given the same list of 25 common words to remember (e.g., desk, gray, plane, car, mask). When 5 minutes had passed, the screen displayed a question asking them whether they felt happy, sad, or neutral.After the participant responded, a new screen was displayed asking them to type in all the words they could remember from the list of 25 words.All participants were given 3 minutes to type the words they remembered.Afterward, the participant was thanked and dismissed.In response to the mood question, a majority of Group A participants said they were happy, a majority of Group B participants said they were sad, and a majority of Group C participants said they were neutral in their mood.Dr.Lonsbary found the following results in response to the number of words remembered. Which of the following should Dr.Lonsbary NOT conclude from her study?

RESEARCH STUDY 10.3: Dr.Phillips is a cognitive-developmental psychologist who studies how children learn mathematical principles.His current interest is in studying how children learn multiplication.He recruits 54 second-graders who have not yet learned how to multiply numbers to participate in his study.He is curious as to whether different teaching styles lead to better mastery of the subject.One condition (A) involves having students read a chapter on multiplication from their textbook.One condition (B) involves having students watch a video of cartoon characters explaining multiplication.One condition (C) involves having students being taught multiplication by a teacher.One condition (D) involves having students being taught multiplication by a fourth-grader.In all conditions, participants spend 30 minutes learning the fundamentals of multiplication and are then given the same 15-question multiplication test.The number of questions answered correctly is recorded.The data are below. Write a question you would ask of Dr.Phillips' study to interrogate each of the four validities.

RESEARCH STUDY 10.2: Dr.Dormeur studies sleep and sleep disorders.She is curious as to whether technology exposure before bedtime causes people to fall asleep more slowly.She recruits a sample of 60 middle-aged women from a local church who reported no history of sleep problems.She creates three conditions.All participants come to the sleep lab for three nights in a row and experience all three conditions.In the first condition (A), participants were asked to play an online game (Candy Crush) on an iPad for 10 minutes prior to going to bed.In the second condition (B), participants were asked to read an article using an iPad that discussed tricks and tips for improving one's score on Candy Crush (which took about 10 minutes).In the third condition (C), participants were asked to read a newspaper article about the inventor of Candy Crush (which took about 10 minutes).With the use of an electroencephalograph (EEG), the researcher measures how long it takes participants to fall asleep. Which of the following designs is Dr.Dormeur using?

Which of the following research designs is used to address possible selection effects?

When conducting an experiment, what is provided by the independent variable?

Using a matched-group design is especially important in which of the following cases?

Which of the following is NOT true of control variables?

RESEARCH STUDY 10.2: Dr.Dormeur studies sleep and sleep disorders.She is curious as to whether technology exposure before bedtime causes people to fall asleep more slowly.She recruits a sample of 60 middle-aged women from a local church who reported no history of sleep problems.She creates three conditions.All participants come to the sleep lab for three nights in a row and experience all three conditions.In the first condition (A), participants were asked to play an online game (Candy Crush) on an iPad for 10 minutes prior to going to bed.In the second condition (B), participants were asked to read an article using an iPad that discussed tricks and tips for improving one's score on Candy Crush (which took about 10 minutes).In the third condition (C), participants were asked to read a newspaper article about the inventor of Candy Crush (which took about 10 minutes).With the use of an electroencephalograph (EEG), the researcher measures how long it takes participants to fall asleep. Dr.Dormeur was concerned that asking participants how long it took them to fall asleep would lead them to suspect that was the purpose of the study.Her decision to measure how long it took participants to go to sleep using the EEG instead of self-report was meant to decrease which of the following?

RESEARCH STUDY 10.3: Dr.Phillips is a cognitive-developmental psychologist who studies how children learn mathematical principles.His current interest is in studying how children learn multiplication.He recruits 54 second-graders who have not yet learned how to multiply numbers to participate in his study.He is curious as to whether different teaching styles lead to better mastery of the subject.One condition (A) involves having students read a chapter on multiplication from their textbook.One condition (B) involves having students watch a video of cartoon characters explaining multiplication.One condition (C) involves having students being taught multiplication by a teacher.One condition (D) involves having students being taught multiplication by a fourth-grader.In all conditions, participants spend 30 minutes learning the fundamentals of multiplication and are then given the same 15-question multiplication test.The number of questions answered correctly is recorded.The data are below. Name two ways that Dr.Phillips could avoid selection threat when he is assigning participants to conditions and explain why each of these methods avoids selection threat.

A variable that the researcher controls is a variable.