Exam 10: Introduction to Simple Experiments

A threat to internal validity occurs only if a potential design confound varies with the independent variable.

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. Using Dr.Phillips' study as an example, explain the difference between a control group and a comparison group.Why did Dr.Phillips' study not have a control group?

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. How many conditions/levels of the independent variable were in Dr.Lonsbary's study?

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 allows Dr.Lonsbary to conclude that she met the temporal precedence rule for causality?

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 is considering doing a follow-up study in which instead of asking participants to listen to music to induce mood, she has them write either a story about a character who just won the lottery or a story about a character who just experienced the death of their spouse.This change in the mood variable is designed to enhance the study's validity.

is used to control order effects in an experiment.

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. Given that there are three conditions/levels of the independent variable, how many orders of the conditions are possible in Dr.Dormeur's study?

Random selection enhances validity and random assignment enhances validity.

Which of the following phrases describes a manipulated variable?

Explain the difference between full counterbalancing and partial counterbalancing.Why would a researcher choose partial counterbalancing over full counterbalancing?

All of the following are advantages of within-groups designs EXCEPT:

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 is NOT a control variable in Dr.Lonsbary's study?

What is the difference between a posttest-only design and a pretest/posttest design? Provide both a benefit and a disadvantage of using a pretest/posttest design.

Generally, what is the main priority for experimental studies?

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 contains which of the following techniques designed to address a threat to construct 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. Which of the following is a dependent variable in Dr.Lonsbary's study?

Which of the following is a threat to internal validity found in within-groups designs but not in independent-groups designs?

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's participants have only agreed to participate in the study for three nights each.Which type of counterbalancing can she use?

What is the primary difference between pretest/posttest designs and within-groups designs?

Which of the following is NOT a reason that a researcher might choose a pretest/posttest design?