Exam 11: More on Experiments: Confounding and Obscuring Variables

Which of the following is NOT a reason that a study might yield a null result?

Which of the following can help prevent testing effects?

Which of the following threats to internal validity can apply even when a control group is used?

The addition of a comparison group can address which of the following threats to internal validity?

Dr.Morimoto is curious as to whether exposing people to violent video games causes them to be more aggressive.He assigns half his participants to play a video game for 5 minutes and the other half to play for 7 minutes.He finds that there is no relationship between playing the game longer and being more aggressive.What might be to blame for this null effect?

Regression is especially problematic in which of the following situations?

Which of the following cannot be found in a one-group, pretest/posttest design?

Dr.Deveraux has conducted a study that has resulted in a null effect.Nonetheless, she suspects that there truly is a causal relationship between her independent and dependent variables.Which of the following is UNLIKELY to be to blame?

RESEARCH STUDY 11.2: Dr.Bloedorn is a health psychologist who researches nutrition.She is curious as to whether a new drink additive will help people consume fewer calories during a meal.The drink additive is a white, odorless, tasteless powder that a person can add to any drink.She collects a random sample of 63 overweight students on campus and measures the calories they eat during lunch using a bomb calorimeter.She then gives this additive to the same 63 participants to use at dinner and measures how many calories they eat (again using the bomb calorimeter). Which of the following threats to internal validity will Dr.Bloedorn NOT be worried about?

Ceiling effects can lead to:

Dr.Sanderson is curious as to whether exposing people to violent video games causes them to be more aggressive.She assigns half her participants to play a violent video game for 5 minutes and the other half to play the same game for 25 minutes.Afterward, she has them play a board game and has a well-trained coder determine whether they are very aggressive in their playing style, barely aggressive, or not at all aggressive.She finds that a vast majority of her participants, regardless of group assignment, are rated as very aggressive.This outcome would be known as a(n):

Explain how within-group variance can obscure between-group differences.

RESEARCH STUDY 11.2: Dr.Bloedorn is a health psychologist who researches nutrition.She is curious as to whether a new drink additive will help people consume fewer calories during a meal.The drink additive is a white, odorless, tasteless powder that a person can add to any drink.She collects a random sample of 63 overweight students on campus and measures the calories they eat during lunch using a bomb calorimeter.She then gives this additive to the same 63 participants to use at dinner and measures how many calories they eat (again using the bomb calorimeter). The addition of a group that does not use the drink additive but adds a similar-looking substance that they think is the additive would help Dr.Bloedorn address which of the following threats to internal validity?

RESEARCH STUDY 11.1: In previous studies, Dr.Schulenberg has established that finding meaning in one's everyday work activities can lead to greater success in the workplace (e.g., productivity, creativity).He is curious as to whether this can happen in the college classroom.Specifically, he is curious whether finding meaning in one's classroom experience can lead to greater academic performance.In the spring semester, he has his teaching assistant randomly assign half the class to write a paragraph each class period about how the material has meaning for their lives (meaning group).The other half writes a paragraph about what they did to prepare for class (preparation group).He does not know which of his students are writing which paragraph, and the students are not aware they are responding to different writing assignments.To measure academic performance, he gives the students a midterm essay exam and a final exam. Which of the following aspects of Dr.Schulenberg's study allows him to prevent observer bias?

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?

Which of the following is a reason why a researcher might choose to conduct a double-blind placebo control group study?

Which of the following things can be done to reduce measurement error?

Testing threats involve , whereas instrumentation threats involve .

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

To be a history threat, the external event must occur: