Mad Scientist 101: Simple Experiments Unleashed
Experimentation Nation!
Experiment Extravaganza
The Causality Chronicles
Obscure Oddities: Navigating the Confounding Maze
Confounding Chronicles: Tales of Variable Intrigue
Variable Wonderland
The League of Extraordinary Variables
Correlation Conundrums
The Bivariate Circus
100
________ is used to control order effects in an experiment.
Counterbalancing
100
When an experiment includes participants experiencing all levels of the independent variable, what type of design is this?
What is a within-groups design?
100
Considering a measure’s face validity is....
a. a good way to interrogate the construct validity of the dependent variable.
b. not necessary in experiments.
c. only done if an experiment uses observational measures.
d. the first step in establishing causation.
a good way to interrogate the construct validity of the dependent variable.
100
A researcher tests two groups and finds they perform equally well because the test is too easy for both. What type of effect occurred?
What is a ceiling effect?
100
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?
a. a weak manipulation
b. an insensitive measure
c. a reverse confound
d. ceiling effect
a. a weak manipulation
100
When assessing the external validity of an association claim, this factor holds the utmost significance.
a. the way the sample was selected from the population
b. the size of the sample
c. the number of subgroups
d. the size of the original population
a. the way the sample was selected from the population
100
If a person is asking whether the variables in an association claim are measured appropriately, what is being interrogated?
construct validity
100
In the case of a factorial design, another term for independent variable is
factor
100
What does the dot represent in the graph?
The dot represents a single participant.
100
A study finds a correlation coefficient of r =.52. This number gives you information about what?
strength and direction of the relationship
200
This threat to internal validity is typically found in within-groups designs but not in independent-groups designs.
practice effects
200
Assigning participants to groups based on rolling a die is an example of what experimental procedure?
What is random assignment?
200
The d score is a standardized measure of the degree to which the independent variable caused a change in the dependent variable. This is also known as the
effect size
200
What type of threat occurs when participants drop out of a study, causing uneven groups?
What is attrition?
200
Which of the following things can be done to reduce measurement error?
a. using less precise measurements
b. using more reliable measurements
c. using a pretest/posttest design
d. increasing unsystematic variance
b. using more reliable measurements
200
The mathematical (alternative) way to describe an interaction is
a difference in differences.
200
The number of main effects that need to be examined is ________ the number of independent variables.
equal to
200
Which of the following phrases might a person encounter in a popular media article that indicates an interaction?
a. “statistically significant”
b. “mixed factorial design”
c. “it depends”
d.“mediator variables”
c. “it depends”
200
Which of the following does NOT depict a statistically significant association?
a. r = .26, 95% CI [–.08, .60]
b. r = .32, 95% CI [.03, .61]
c. r = -.44, 95% CI [–.32, –.56]
d. r = –.28, 95% CI [–.06, –.50]
a. r = .26, 95% CI [–.08, .60]
200
Which of the following studies would benefit the most from a replication study?
a. a study with a large correlational coefficient
b. a study with a small sample size
c. a study with a large effect size
d. a study with a narrow confidence interval
b. a study with a small sample size
300
A professor tests whether a new study app improves exam scores. Students choose whether to use the app or study normally. The app group scores higher, but they may have been more motivated before the study started. Random assignment would have helped reduce what problem?
Selection effects
300
A study compares participants taught multiplication by reading a textbook, watching a video, or having an instructor. What is this an example of?
What is a between-groups design?
300
When participants are sorted from lowest to highest on a variable, grouped into sets of two, and then one person from each set is assigned at random to each of the experimental groups, this is called
matching
300
A study on the effects of sleep deprivation is disrupted when a power outage affects the sleep schedule of half the participants. What threat is this?
What is a history threat?
300
When interrogating experiments, on which of the big validities should a person focus?
Internal validity
300
Ceiling effects may lead to this outcome, resulting in minimal variation among groups. What is the correct response?
small variance between groups.
300
According to the textbook, why is it important to study interactions?
Many outcomes in psychology are interactions.
300
Dr. Gavin is conducting a 2 × 4 independent-groups factorial design. How many independent variables are in his study?
2
300
In a study on weight loss, participants in the control group are given a sugar pill instead of the actual supplement. What is this process called?
What is a placebo?
300
A researcher finds that sleep and memory scores are correlated at r = .20. Based on the effect size guidelines we discussed, how would you describe the magnitude and direction of this correlation?
This is a moderate positive effect. As sleep increases, memory scores tend to increase.
400
The question “Can the causal relationship generalize to other people, places, and times?” refers to what type of validity?
external
400
A researcher uses a within-groups design to measure memory before and after listening to music. What type of variable is the "before and after" measure?
What is a repeated measure?
400
When assessing the construct validity of the dependent variable in an experiment, which crucial question should be posed?
“How well was this variable measured?”
400
Researchers in a study fail to control the temperature of the testing room, which causes participants to perform differently depending on their discomfort level. What is this an example of?
What is situation noise?
400
!!!!!!!!!!!!!!!!!!!!
When a double-blind study is not possible, an acceptable alternative may be
a masked design
400
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?
design confound
400
A researcher tests whether study method and sleep affect exam scores. Students either use flashcards or practice tests, and they either sleep 4 hours or 8 hours before the exam.
Average exam scores:
Flashcards + 4 hours sleep = 70
Flashcards + 8 hours sleep = 80
Practice tests + 4 hours sleep = 78
Practice tests + 8 hours sleep = 88
Based on these means, what are the two main effects?
Provide the sentence.
There is a main effect of study method, those who studied with practice tests (M=83) had higher scores overall than those who studied with flashcards (M=75). There is also a main effect of sleep because students who slept 8 hours (M=84) scored higher overall than students who slept 4 hours (M=74).
400
Dr. Green is interested in conducting a 2 × 2 × 3 within-group factorial design, with 20 participants in each cell. How many participants does she need overall?
20
400
Name three disadvantages of within-groups designs.
(a) Within-groups designs have the potential for order effects;
(b) they have an increased risk for demand characteristics;
(c) it may not be realistic to have participants provide repeated measures;
(d) it may be impossible for participants to experience something twice (as in the example from the textbook of learning to ride a bike twice).
500
Explain why experiments are better than your own personal experience at making causal claims,
Experiments provide a comparison group, whereas personal experience does not provide a comparison group. With experiments, the question “compared to what?” can be answered. One knows one’s own experience in given situations, but there’s no way of knowing if those experiences are different from or the same as other people’s experiences in those same situations.
500
A study introduces a manipulation check to confirm whether participants experienced the intended mood. What is this check addressing?
What is construct validity?
500
Explain why control variables are necessary in experiments and why they are not actually variables.
Control variables are not actually variables because they do not actually vary. Control variables are necessary in experiments to deal with threats to internal validity. Control variables are those aspects of a study that are held constant or equal across groups and that allow researchers to rule out alternate explanations for the causal relationships.
500
A researcher conducts an experiment and finds a significant main effect but no significant interaction. What does this mean?
What is the independent variable affected the outcome, but the effect did not depend on another variable?
500
What is a double-blind study? Explain how this design addresses both the issue of demand characteristics and the issue of observer bias.
A double-blind study is a study in which neither the participants nor the researchers who evaluate them know who is in the treatment group and who is in the comparison group. When participants are kept unaware of their group assignment, they cannot change their behavior to match any expectation (demand characteristics). And when the observers are kept unaware of participants’ group assignment, they cannot change their rating behavior/data collection to match the hypothesized expectations (observer bias).
500
Explain why null effects are important in science but are hard to find in popular media.
Null effects are important in science because it is important to understand that some things are not related, some therapies do not work, and some differences do not exist. Null effects are hard to find in popular media because there is a publishing bias against null effects. Generally, newspapers and magazines prefer to print articles about relationships, differences, and effective treatments.
500
Dr. Yared is interested in memorization techniques and motivation. He splits his participants into four equal groups of 20 people each and gave each participant a list of 30 words to try to memorize in three minutes. Two groups were told to repeat the words silently to themselves and two groups were told to make up a story using the words. Two groups were offered 10 cents per word they recalled and two were offered $1 per word. The table shows how many words each group was able to recall.
What are the marginal means for monetary reward?
14 and 14.5
500
A researcher tests whether caffeine affects reaction time differently for morning people and night people. Lower reaction time means faster performance.
Average reaction times:
Morning people + no caffeine = 300 ms
Morning people + caffeine = 280 ms
Night people + no caffeine = 340 ms
Night people + caffeine = 285 ms
Based on these means, is there an interaction between chronotype and caffeine?
Yes there is an interaction.
Night people with no caffeine were slowest at 340 ms, and morning people with caffeine were fastest at 280 ms. Caffeine improved performance for both groups, but it had a larger effect for night people, so the effect of caffeine depended on chronotype.
"especially when"
500
Draw a scatterplot for the following three associations:
a. a curvilinear association
b. a positive association with a large effect size
c. a zero association
Scatterplot A should show a curvilinear relationship (either a U relationship or an inverted U relationship).
Scatterplot B should show a steep line pointed upward, with dots closely grouped around the line.
Scatterplot C should show a group of dots showing no discernable pattern, OR a flat vertical line with dots showing no discernable pattern, OR a curvilinear relationship.