AP Psych Unit 0

Hindsight Bias

The tendency to believe, after learning an outcome, that one would have foreseen it ("I knew it all along").

Overconfidence

The tendency to think we know more or are more accurate about the future than we actually are.

Operational Definition

A precise, carefully worded description of concepts/variables in a way that is measurable and allows for exact replication (e.g., measuring intelligence via SAT score).

Hypothesis

A testable prediction implied by a theory.

Independent Variable (IV)

The experimental factor that is manipulated by the researcher to examine its effect.

Dependent Variable (DV)

The outcome factor; the variable that is measured to see how it changes in response to manipulations.

Experimental Group

In an experiment, the group exposed to the treatment (one version of the independent variable).

Control Group

In an experiment, the group not exposed to the treatment; serves as a comparison for evaluating the effect of the treatment.

Confounding Variable

A factor other than the factor being studied that might produce an effect in an experiment.

Random Assignment

Assigning participants to experimental and control groups by chance, minimizing preexisting differences between groups.

Placebo Effect

Experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition.

Replication

Repeating the essence of a research study (often with differing variables/participants) to confirm reliability.

Peer Review

A process where independent scientific experts check research for bias, methodology flaws, and mistakes prior to publication.

Population

All the cases in a group being studied, from which samples may be drawn.

Random Sample

A sample that fairly represents a population because every member has an equal chance of being included.

Representative Sample

A sample carefully selected so that the researchers mirror a specific target group (e.g., selecting only 11th graders).

Case Study

A non-experimental technique in which one individual or group is studied in depth to uncover universal principles.

Naturalistic Observation

Observing and recording behavior in naturally occurring situations without interfering or controlling the situation.

Meta-Analysis

A statistical technique for combining the results of multiple independent studies to determine overall trends.

Correlation

A measure of the extent to which two factors vary together, and thus how well either factor predicts the other.

Longitudinal Study

A research design in which the same individuals are observed and retested repeatedly over a very long period.

Cross-Sectional Study

A research design that compares individuals of different groups/ages at a single point in time.

Correlation Coefficient

A statistical index of the relationship between two variables, ranging from -1.00 to +1.00.

Positive Correlation

A relationship where two variables move in the same direction (both increase or both decrease together).

Negative Correlation

A relationship where two variables move in opposite directions (as one increases, the other decreases).

Correlation vs. Causation Rule

Correlation indicates the possibility of a relationship, but it does NOT prove causation.

Illusory Correlation

Perceiving a relationship between variables even when no real relationship exists (e.g., wearing a lucky jersey to win).

Qualitative Data

Subjective, non-numerical data involving user behavior, emotions, open-ended verbal responses, and experiences.

Quantitative Data

Objective, numerical data expressed through numbers, graphs, and charts (e.g., Likert scales).

Central Tendency

Descriptive summary measures of a data set's center, including the mean, median, and mode.

Standard Deviation

A computed measure of how much scores vary around the mean score in a distribution.

Empirical Rule (68-95-99.7)

In a normal curve: 68% of data falls within 1 SD of the mean, 95% within 2 SDs, and 99.7% within 3 SDs.

Null Hypothesis

A statistical statement assuming there is NO difference between groups or NO relationship between variables.

P-Value

The probability of obtaining test results at least as extreme as observed, assuming the null hypothesis is true.

Statistical Significance Cutoff

A p-value of less than 0.05 (p < 0.05), which leads to rejecting the null hypothesis.

Bimodal Distribution

A distribution displaying two distinct peaks (modes), indicating two clear groups within a dataset.

Positively Skewed Distribution

A distribution containing a cluster of low scores with a tail pulling toward high values (mean > median).

Negatively Skewed Distribution

A distribution containing a cluster of high scores with a tail pulling toward low values (mean < median).

Regression Towards the Mean

The statistical tendency for extreme scores/outcomes to fall back toward their average on subsequent re-testing.

Deception in Research

Misleading participants about the true purpose/methods of a study; requires mandatory debriefing.

Debriefing

The post-experimental explanation of a study, including its purpose and any deceptions, to participants.

Informed Consent

An ethical principle requiring research participants to be told enough to enable them to choose whether to participate.

Informed Assent

Agreement to participate in research obtained from minors or individuals unable to give legal consent.

Confidentiality

The ethical requirement that participant data must remain anonymous unless explicit consent is given.

Institutional Review Board (IRB)

An administrative body that reviews research proposals to ensure human participants are not harmed.

Experimenter Bias

The influence of a researcher's expectations or beliefs on the outcome of a study.

Social Desirability Bias

The tendency of survey respondents to answer questions in a manner that will be viewed favorably by others.

Double-Blind Procedure

An experimental procedure in which both research participants and staff are ignorant ("blind") to group assignments.

Single-Blind Procedure

An experimental procedure in which participants are unaware of their group assignment, but researchers know.

Why is standard deviation more useful than the range when evaluating test score variability?

The range only accounts for extreme high and low scores (vulnerable to outliers), whereas standard deviation measures how every score varies around the mean.

In a drug trial, what does it mean if researchers "fail to reject the null hypothesis"?

It means there is no statistically significant difference between the drug group and the placebo group; any observed difference was due to random chance.

If a study yields a p-value of p = 0.02, how should the researchers interpret the result?

Since p < 0.05, the result is statistically significant, meaning there is only a 2% likelihood the outcome occurred by random chance. Reject the null hypothesis.

Why is a correlation coefficient of r = -0.88 stronger than a correlation coefficient of r = +0.62?

The strength of a correlation is determined by its absolute value (distance from zero), regardless of the positive or negative sign.

1. A student is interested in knowing how widely the academic aptitude of college-bound students varies at her school. Which of the following statistical methods should she use to determine how much students' SAT scores vary from the school's average SAT score? a. Correlation coefficient b. Mean c. Percentile rank d. Standard deviation

d. Standard deviation

2. Which method should a psychology researcher use if she is interested in testing whether a specific reward in a classroom situation causes students to behave better? a. Case study b. Experiment c. Survey d. Correlation

b. Experiment

3. In a perfectly normal distribution of scores, which of the following statements is true? a. The mean, median, and mode are all the same number. b. The mode is equal to the standard deviation. c. The scores are positively correlated. d. There is a positive skew to the distribution of data.

a. The mean, median, and mode are all the same number.

4. Which of the following describes the placebo effect? a. Students in art class are not told that their work will be evaluated for a scholarship so they do not submit their best work. b. Participants in an experiment do not know if they are in the experimental or control group so their attitudes about the study are unaffected. c. Participants in a drug study are given an inert pill instead of the drug and behave as though they were given the drug. d. Only women are chosen for a study, even though the population included men.

c. Participants in a drug study are given an inert pill instead of the drug and behave as though they were given the drug.

5. Which of the following represents naturalistic observation? a. Researchers go to the mall and distribute surveys about the stores in the mall. b. Researchers bring participants into a laboratory to see how they respond to a puzzle with no solution. c. A principal looks at the relationship between the number of student absences and their grades. d. Researchers observe students' seating patterns in the cafeteria.

d. Researchers observe students' seating patterns in the cafeteria.

6. "Monday morning quarterbacks" rarely act surprised about the outcome of weekend football games. This tendency to believe they knew how the game would turn out is best explained by which psychological principle? a. Overconfidence b. Hindsight bias c. Illusory correlation d. Random sampling

b. Hindsight bias

7. Which of the following statements best describes the graph below? [Scatterplot showing points in a straight line sloping up and to the right] a. This is a scatterplot of a perfect positive correlation. b. This is a scatterplot of a weak negative correlation. c. This is a histogram of a weak positive correlation. d. This is a histogram of a perfect positive correlation.

a. This is a scatterplot of a perfect positive correlation.

8. A journalism student is writing an article about her school's new cell-phone policy, and she'd like to interview a random sample of students. Which of the following is the best example of a random sample? a. The writer arrives at school early and interviews the first five students who come through the main entrance. b. The writer pulls the names of five students from a hat that contains all students' names. She interviews the five selected students. c. The writer asks her teacher if she can distribute a brief survey to the students in her AP® Psychology class. d. The writer passes out brief surveys to 50 students in the hall and uses the 18 surveys returned to her as the basis of her article.

b. The writer pulls the names of five students from a hat that contains all students' names. She interviews the five selected students.

9. Which of the following is a positive correlation? a. As study time increases, students achieve lower grades. b. As levels of self-esteem decline, levels of depression increase. c. The more people exercise, the better they sleep. d. Gas mileage decreases as vehicle weight increases.

c. The more people exercise, the better they sleep.

10. Why is random assignment of participants to groups an important aspect of a properly designed experiment? a. If the participants are randomly assigned, the researcher can assume that each group is similar to each other at the beginning of the study. b. By randomly assigning participants, the researcher knows that whatever is learned from the experiment will also be true for the population from which the participants were selected. c. If participants are not randomly assigned, it is impossible to replicate the experiment. d. Statistical analysis cannot be performed on an experiment if random assignment is not used.

a. If the participants are randomly assigned, the researcher can assume that each group is similar to each other at the beginning of the study.

11. A social psychology researcher operationally defines aggression as loudness of a noise blast (ranging from 0 to 105 decibels) supposedly delivered to a stranger. This research method is best described as a. inferential. b. qualitative. c. quantitative. d. replication.

c. quantitative.

12. Which of the following is a potential problem with case studies? a. They provide too much detail, and the researcher is likely to lose track of the most important facts. b. They are generally too expensive to be feasible. c. The information learned may not apply to the wider population. d. The dependent variable is difficult to operationally define in a case study.

c. The information learned may not apply to the wider population.

13. Which of the following is an ethical principle regarding experimental research on humans? a. Researchers must protect participants from needless harm and discomfort. b. Regardless of the research design, all participants sign an informed consent form. c. Personal information about individual participants can only be revealed in peer-reviewed journals. d. Participants should always be informed of the hypothesis of the study before they agree to participate.

a. Researchers must protect participants from needless harm and discomfort.

14. There is a negative correlation between TV watching and grades. What can we conclude from this research finding? a. We can conclude that this is an illusory correlation. b. We can conclude that TV watching leads to lower grades. c. We can conclude that TV watching leads to higher grades. d. We can conclude that a student who watches a lot of TV is likely to have lower grades.

d. We can conclude that a student who watches a lot of TV is likely to have lower grades.

15. Which of the following groups of scores would have the smallest standard deviation? a. 20, 40, 60, 80, 100 b. 5, 15, 25, 35, 45 c. 2, 4, 6, 8, 10 d. 100, 200, 300, 400, 500

c. 2, 4, 6, 8, 10

21. Kai scored in the 90th percentile in a math competition in her state. Which of the following statements is true of Kai's score? a. Her score is higher than 10 percent of others in the competition. b. Her score is lower than 89 percent of others in the competition. c. Her score is higher than 90 percent of others in the competition. d. Her score is an outlier in this competition.

c. Her score is higher than 90 percent of others in the competition.

22. Paulette is taking a survey. Instead of being honest, she is answering it in a way that she thinks will please the researchers. Paulette is showing a(n) a. hindsight bias. b. sampling bias. c. experimenter bias. d. social desirability bias.

d. social desirability bias.