Question 1

Explain what a manipulation check is and how it can be used to address issues of weak manipulations and insensitive measures.

Accepted Answer

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Question 2

Which of the following threats to internal validity would result in group differences prior to the start of the study?
A)Design confound
B)Selection effect
C)Order effect
D)Maturation effect

Accepted Answer

A selection effect occurs when the groups being compared are already different prior to the start of the study. This could be due to nonrandom assignment or self-selection into groups.

Question 3

Name the three threats to internal validity that can occur in studies regardless of the use of a comparison group. Why doesn't a comparison group help in these cases?

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Question 4

Dr. Anderson conducted a study investigating whether exercising immediately before an exam boosted cognitive abilities. She randomly assigned participants to either do jumping jacks or count to 60 before giving them a geometry test. She did not find any differences between groups but believes there may have been a ceiling effect. What might be a clue that this was the case?
A)All participants' scores are centered around 100% correct.
B)Participants in the counting group showed more variability in scores.
C)Participants in the exercise group took longer to complete the test.
D)Some participants verbally noted that the test was too easy.

Accepted Answer

A clue that there may have been a ceiling effect is if all participants' scores are centered around 100% correct. This means that the task may have been too easy for all participants and there was no room to improve further, regardless of whether they exercised or not.

Question 5

Dr. Gong conducts a study where she randomly assigns participants to different experimental conditions. The testing for each condition occurs in a different room of the psychology building. After collecting her data, she learns that the air conditioning in one of the rooms had been turned off during data collection. Which of the following threats to internal validity should Dr. Gong be concerned with?
A)Design confound
B)Selection effect
C)Order effect
D)Maturation effect

Accepted Answer

A design confound occurs when a second variable unintentionally varies systematically along with the independent variable. In this case, the temperature in one room (due to the air conditioning being off) could have affected the participants' performance or responses, thus acting as an unintended second variable that varies across conditions. This threatens the study's internal validity by introducing an alternative explanation for any observed effects.

Question 6

Dr. Paddock is a counseling psychologist who is interested in decreasing adjustment issues in first-year college students. She is curious if having students create collages of their first few weeks of school and then mail them home will help students feel they have integrated their new life with their old and, as a result, will help them feel less homesick. She samples a group of 100 incoming college freshmen at her university and measures how homesick they are during the first week of school. During week 4 of school, she has them make the collage and send it home. During week 7 of school, she measures their homesickness again. She notices a significant reduction in the amount of homesickness from the pretest to the posttest and concludes that her treatment is effective.
Imagine in Dr. Paddock's study that only 90 of the original participants completed the measure of homesickness during week 7 (10 participants had left the university and were unavailable). What kind of threat to internal validity does this pose? How does this affect her conclusion that her treatment for homesickness worked?

Accepted Answer

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Question 7

What is a double-blind study? Explain how this design addresses both the issue of demand characteristics and the issue of observer bias.

Accepted Answer

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Question 8

After finding a null result in her study, a researcher decides to conduct a follow-up study where she limits who the findings will generalize to. Which cause of within-group variance is she trying to reduce?
A)Measurement error
B)Individual differences
C)Situation noise
D)Lack of power

Accepted Answer

By limiting who the findings will generalize to, the researcher is attempting to reduce individual differences within the group. This approach aims to make the participants more similar to each other, thereby reducing the variance attributed to differences between individuals.

Question 9

What can researchers do to reduce the risk of measurement error?
A)Select measures that have high reliability and validity
B)Make conditions comparable in each experimental group
C)Use large sample sizes
D)Use a strong manipulation

Accepted Answer

Selecting measures that have high reliability and validity is the best choice to reduce the risk of measurement error. Reliability refers to the consistency of a measure, while validity refers to the accuracy of a measure. Choosing measures that are both reliable and valid will help ensure that the results are accurate and not affected by measurement error. Making conditions comparable in each experimental group, using large sample sizes, and using a strong manipulation can also help reduce measurement error, but selecting measures with high reliability and validity is the most important factor.

Question 10

Dr. Paddock is a counseling psychologist who is interested in decreasing adjustment issues in first-year college students. She is curious if having students create collages of their first few weeks of school and then mail them home will help students feel they have integrated their new life with their old and, as a result, will help them feel less homesick. She samples a group of 100 incoming college freshmen at her university and measures how homesick they are during the first week of school. During week 4 of school, she has them make the collage and send it home. During week 7 of school, she measures their homesickness again. She notices a significant reduction in the amount of homesickness from the pretest to the posttest and concludes that her treatment is effective.
Imagine in Dr. Paddock's study that only 90 of the original participants completed the measure of homesickness during week 7 (10 participants had left the university and were unavailable). Name two things that Dr. Paddock can do to address this possible threat to internal validity and why these should be done.

Accepted Answer

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Question 11

To avoid insensitive measures, it is important to use measures that include:
A)large differences between the levels of the variable.
B)measurement error.
C)ceiling effects.
D)multiple increments of the variable.

Accepted Answer

Using multiple increments of the variable can help avoid insensitive measures as it allows for more precise measurement and can capture smaller differences between levels of the variable. A larger difference between levels of the variable (option A) may not necessarily lead to a more sensitive measure, and measurement error (option B) and ceiling effects (option C) can actually contribute to insensitivity.

Question 12

Using the same setting and consistent protocols for each participant in a study will reduce the effect of:
A)measurement error.
B)individual differences.
C)situation noise.
D)floor effects.

Accepted Answer

Consistent protocols and settings will reduce the effect of situation noise, which refers to the variability in the environment or context in which measurements are taken. This can include differences in lighting, temperature, noise levels, etc. By minimizing such variability, researchers can increase the internal validity of their study, meaning that the results are more likely to accurately reflect the relationship between the variables of interest rather than being affected by extraneous factors. However, it may not completely eliminate individual differences or measurement error, as these can be inherent to the participants or the measures used, respectively. Floor effects, which refer to situations where participants are performing at the lowest possible level on a task, may or may not be affected by consistent protocols and settings, depending on the nature of the task and the participants involved.

Question 13

Armand conducts a study for his research method class. He is curious as to whether watching romantic movies makes people more committed to their romantic relationship. He collects a sample of men in dating relationships and divides them into two groups. One group watches a 5-minute clip of a movie in which the main characters are having a romantic first date. The second group watches a 5-minute clip from the same movie in which the main characters break up. After the participants watch the movie clip, they are then asked to write a sentence about their relationship. Armand counts the number of uses of the words we and us as a measure of commitment. After conducting the study, he finds that there is not a statistically significant difference between his two groups.
Provide three reasons why Armand's study may have resulted in null effects.

Accepted Answer

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Question 14

Ceiling effects can affect:
A)certain groups more than others.
B)independent variables only.
C)dependent variables only.
D)both independent and dependent variables.

Accepted Answer

Ceiling effects can happen with both independent and dependent variables. When a ceiling effect occurs with an independent variable, it means that the variable has reached its maximum value and cannot be increased further. This can limit the range of the dependent variable and affect the results. On the other hand, when a ceiling effect occurs with a dependent variable, it means that the variable has reached its maximum score or level, and cannot be improved further, which can limit the ability to measure any differences between groups or treatments.

Question 15

Ceiling effects can lead to:
A)large variance within groups.
B)large variance between groups.
C)small variance between groups.
D)all participants performing poorly.

Accepted Answer

Ceiling effects occur when the test or measure is too easy or the ability of the participants is high. This can lead to a situation where many or all participants score at the maximum level, resulting in very little variance within the group. Therefore, the choice that reflects this outcome is (C) small variance between groups.

Question 16

Dr. Merrick designs a study comparing the effects of mindfulness training to cognitive training on flexible thinking. In designing this study, what would be an appropriate manipulation check?
A)Testing that the flexible thinking task is hard enough to show group differences
B)Measuring heart rate to ensure that mindfulness has a calming effect
C)Ensuring that no participants had prior experience with mindfulness training
D)Adding a third group that receives flexibility training

Accepted Answer

The answer of Dr. Merrick designs a study comparing the...

Question 17

Dr. Paddock is a counseling psychologist who is interested in decreasing adjustment issues in first-year college students. She is curious if having students create collages of their first few weeks of school and then mail them home will help students feel they have integrated their new life with their old and, as a result, will help them feel less homesick. She samples a group of 100 incoming college freshmen at her university and measures how homesick they are during the first week of school. During week 4 of school, she has them make the collage and send it home. During week 7 of school, she measures their homesickness again. She notices a significant reduction in the amount of homesickness from the pretest to the posttest and concludes that her treatment is effective.
What is a comparison group? What kind of comparison group could Dr. Paddock add to her study to address several threats to internal validity? (In other words, what would this comparison group do/not do?) Explain why this addition would help address threats to internal validity.

Accepted Answer

The answer of Dr. Paddock is a counseling psychologist who...

Question 18

Dr. Paddock is a counseling psychologist who is interested in decreasing adjustment issues in first-year college students. She is curious if having students create collages of their first few weeks of school and then mail them home will help students feel they have integrated their new life with their old and, as a result, will help them feel less homesick. She samples a group of 100 incoming college freshmen at her university and measures how homesick they are during the first week of school. During week 4 of school, she has them make the collage and send it home. During week 7 of school, she measures their homesickness again. She notices a significant reduction in the amount of homesickness from the pretest to the posttest and concludes that her treatment is effective.
Imagine in Dr. Paddock's study that the pretest scores were incredibly high, indicating a large amount of homesickness in her sample. What kind of threat to internal validity does this pose? How does this affect her conclusion that her treatment for homesickness worked?

Accepted Answer

The answer of Dr. Paddock is a counseling psychologist who...

Question 19

Armand conducts a study for his research method class. He is curious as to whether watching romantic movies makes people more committed to their romantic relationship. He collects a sample of men in dating relationships and divides them into two groups. One group watches a 5-minute clip of a movie in which the main characters are having a romantic first date. The second group watches a 5-minute clip from the same movie in which the main characters break up. After the participants watch the movie clip, they are then asked to write a sentence about their relationship. Armand counts the number of uses of the words we and us as a measure of commitment. After conducting the study, he finds that there is not a statistically significant difference between his two groups.
Armand's professor suggests that the null effect may be due to insufficient between-group variance. Describe two ways that Armand's study may have had poor between-group variance.

Accepted Answer

The answer of Armand conducts a study for his research...

Question 20

Dr. Paddock is a counseling psychologist who is interested in decreasing adjustment issues in first-year college students. She is curious if having students create collages of their first few weeks of school and then mail them home will help students feel they have integrated their new life with their old and, as a result, will help them feel less homesick. She samples a group of 100 incoming college freshmen at her university and measures how homesick they are during the first week of school. During week 4 of school, she has them make the collage and send it home. During week 7 of school, she measures their homesickness again. She notices a significant reduction in the amount of homesickness from the pretest to the posttest and concludes that her treatment is effective.
Name two threats to internal validity that are likely to be present in Dr. Paddock's study, given her particular design. What other explanation do these threats provide for the results found by Dr. Paddock?

Accepted Answer

The answer of Dr. Paddock is a counseling psychologist who...

Quiz 11: More on Experiments: Confounding and Obscuring Variables

Explain what a manipulation check is and how it can be used to address issues of weak manipulations and insensitive measures.

Which of the following threats to internal validity would result in group differences prior to the start of the study?

Name the three threats to internal validity that can occur in studies regardless of the use of a comparison group. Why doesn't a comparison group help in these cases?

What is a double-blind study? Explain how this design addresses both the issue of demand characteristics and the issue of observer bias.

After finding a null result in her study, a researcher decides to conduct a follow-up study where she limits who the findings will generalize to. Which cause of within-group variance is she trying to reduce?

What can researchers do to reduce the risk of measurement error?

To avoid insensitive measures, it is important to use measures that include:

Using the same setting and consistent protocols for each participant in a study will reduce the effect of:

Ceiling effects can affect:

Ceiling effects can lead to:

Dr. Merrick designs a study comparing the effects of mindfulness training to cognitive training on flexible thinking. In designing this study, what would be an appropriate manipulation check?