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A researcher wants to see if the amount of sleep participants get at night affects their memory. The independent variable (IV) in this study is:
Amount of sleep (# hours)
This concept refers to how well the results of a study can be applied to the larger population the researcher is interested in.
Generalizability
The three most common measures of central tendency are mean, median, and this.
Mode
A symmetrical, bell-shaped distribution in which the mean, median, and mode are approximately equal is called this:
Normal curve / normal distribution
A researcher defines “stress” as a participant's score on a 20-question stress inventory. This is an example of
operational definition
Explain the difference between random sampling and random assignment
Random sampling determines who participates in the study.
Random assignment determines which group participants join.
Before participating in most psychological research, participants should be given enough information to make an informed decision about whether to participate.
Informed consent
In an experiment testing whether background music affects test scores, the test scores are this variable:
Dependent variable (DV)
A researcher wants to study American teenagers, but only surveys 100 students from one private school. What potential problem does this create?
Limits generalizability--
Results may only apply to teenagers with a private school education / from higher socioeconomic status (families can afford private school)
For the data set 4, 5, 5, 6, 20, this measure would be least affected by the extreme score of 20.
Median
A distribution with a long tail extending toward the higher scores is called:
positively skewed distribution
An unexpected variable that affects the outcome of an experiment and makes it difficult to determine whether the IV caused the DV is called:
confounding variable
A participant receives an inactive pill but experiences an improvement because they believe they received the real treatment. This is an example of:
placebo effect
According to this guideline, researchers must take reasonable steps to protect participants from unnecessary physical or psychological harm.
protection from harm
Researchers randomly place participants into a group that receives the treatment and a group that does not. The process of putting participants into these groups is called:
Random assignment
Explain the difference between random sampling and random assignment.
Random sampling determines who gets selected for the study from the population. Random assignment determines which group participants are placed into once they are in the study.
In the data set 2, 3, 3, 4, 18, this measure of central tendency is most affected by the extreme score of 18.
The mean
Two groups have identical means, but Group A has SD = 2 and Group B has SD = 15. What does this tell you?
Group B's scores have much greater variability/spread than Group A's scores.
When scientists repeat a study to determine whether they can obtain similar results, this is called:
replication
After a basketball player scores 40 points in one game, someone says, “I knew he was going to have an amazing game!” This demonstrates:
hindsight bias
After a study involving deception, researchers must explain the true purpose of the study to participants. This is called:
Debriefing
This is the name for entire group of people that a researcher wants their findings to apply to.
Target population
In an experiment investigating whether eating breakfast improves academic performance, the students who eat breakfast before taking a general knowledge test belong to this group:
Experimental group / treatment group
The difference between the highest and lowest scores is called this measure of variability.
range
According to the 68-95-99.7 rule, approximately what percentage of scores in a normal distribution fall within two standard deviations of the mean?
95%
A researcher obtains p = .02. Using the conventional p < .05 standard, the result is considered:
statistically significant
Researchers study the same 100 people every year from ages 15 through 25. What type of study is this?
Longitudinal
Researchers must protect participants' personal information and identities.This is called:
confidentiality/privacy protections
A researcher randomly selects 200 students from a list of every student in a school. This process is called:
random sampling / random selection
You conduct a study on 200 students at your school. You want to generalize your findings to teenagers across America. Name one reason your study might have limited generalizability.
The sample may not adequately represent American teenagers because it comes from only one school.
wo classes both have an average score of 80. Class A's scores are tightly clustered around 80. Class B's scores range from 40 to 100. Which class has the larger standard deviation?
Class B
A test has a mean of 75 and a standard deviation of 5. Approximately 68% of students should score between which two numbers?
70 and 80
A researcher believes their new therapy works. While analyzing the results, they focus heavily on results that support their hypothesis. What type of bias will affect the outcome of this study?
Confirmation bias
Researchers combine the findings from 40 separate studies examining the relationship between sleep and memory. What type of study is this?
Meta-analysis
A researcher wants to deceive participants because knowing the true purpose would influence their behavior. Name at leasg one thing that needs to be true for an IRB to approve research involving deceptioN:
A psychologist wants to determine whether phone notifications interfere with students' ability to remember information.
Students are randomly assigned to either receive notifications while studying or have their notifications turned off.
Identify the IV, DV, experimental group, and control group.
A researcher wants to study whether sleep affects reaction time. She recruits 200 teenagers but allows students to choose whether they want to sleep 8 hours or only 5 hours before the experiment.
What important feature of experimental design is missing?
Random assignment
Two groups take the same test.
Group A: Mean = 80, SD = 2
Group B: Mean = 80, SD = 15
What can you conclude about the two groups?
They have the same average performance, but Group B has much greater variability.
A student receives an unusually low score on one exam but scores closer to their usual average on the next exam. What statistical phenomenon may help explain this?
regression toward the mean
A researcher claims that “social media use causes loneliness.” However, the researcher simply asks participants, “Do you use social media a lot?” and “Do you feel lonely?” Participants answer however they interpret those questions.
What important research-method concept is missing?
operatioanl definition ("social media use")
Researchers compare 15-, 25-, and 35-year-olds during the same year. What type of study is this?
Cross-sectional study
A researcher wants to determine whether a new medication reduces anxiety. Participants know whether they received the medication or the placebo, and the researchers also know which participants received each treatment.
Why might this be problematic?
Participants' expectations and researcher expectations could influence the results. A double-blind design could reduce these potential biases.