click below

click below

Normal Size Small Size show me how

# 1400 Stats-n-Researc

### AP Psychology Statistics and Research Methods

Term | Definition |
---|---|

Hindsight bias | The tendency to believe, after learning an outcome, that one would have foreseen it. (Also known as the I-knew-it-all-along phenomenon.) |

Critical thinking | Thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions. |

Theory | A testable explanation using an integrated set of principles for a set of facts or observations and predicts behaviors or events. |

Hypothesis | A testable prediction, often implied by a theory, describing the relationship among variables in a study. |

Operational definition | Specific descriptions of concepts involving the conditions of a scientific study; stated in terms of how the concepts are to be measured or what operations are being employed to produce them. |

Replication | Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances. |

Case study | An observation technique in which one person is studied in depth in the hope of revealing universal principles. |

Survey | A technique for ascertaining the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them. |

False consensus | The tendency to overestimate the extent to which others share our beliefs and behaviors. |

Population | All the cases in a group, from which samples may be drawn for a study. |

Random sample | A sample that fairly represents a populations because each member has an equal chance of inclusion. |

Naturalistic observation | Observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation. |

Correlation | A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. The correlation coefficient is the mathematical expression of the relationship, ranging from -1 to +1. |

Scatterplot | A graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation. |

Illusory correlation | The perception of a relationship where none exists. |

Experiment | A research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). The experimenter aims to control other relevant factors. |

Double-blind procedure | An experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies. |

Placebo effect | Experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which is assumed to be an active agent. |

Experimental condition | The condition of an experiment that exposes participants to the treatment, that is, to one version of the independent variable. |

Control condition | The condition of an experiment that contrasts with the experimental condition and serves as a comparison for evaluating the effect of the treatment. |

Random assignment | Assigning participants to experimental and control conditions by chance, thus minimizing preexisting differences between those assigned to the different groups. |

Independent variable (IV) | A stimulus condition so named because the experimenter changes it independently of all the other carefully controlled experimental conditions. |

Dependent variable | The outcome factor; the variable that may change in response to manipulations of the independent variable. The measured outcome of a study; the responses of the subjects in a study. |

Mode | The most frequently occurring score(s) in a distribution. |

Mean | The arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores. |

Median | The middle score in a distribution; half the scores are above it and half are below it. |

Range | The difference between the highest and lowest scores in a distribution. |

Standard deviation | A computed measure of how much scores vary around the mean score. |

Statistical significance | A statistical statement of how likely it is that an obtained result occurred by chance. |

Culture | The enduring behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next. |

Scientific method | A five-step process for empirical investigation of a hypothesis under conditions designed to control biases and subjective judgments. |

Empirical investigation | An approach to research that relies on sensory experience and observation as research data. |

Random presentation | A process by which chance alone determines the order in which the stimulus is presented. |

Ex post facto | Research in which we choose subjects based on a pre-existing condition. |

Longitudinal study | A type of study in which one group of subjects is followed and observed (examined, surveyed, etc.) for an extended period. |

Cross-sectional study | A study in which a representative cross section of the population is tested or surveyed at one specific time. |

Cohort-sequential study | A research method in which a cross section of the population is chosen and then each cohort is followed for a short period. |

Personal bias | The researcher allowing personal beliefs to affect the outcome of a study. |

Expectancy bias | The researcher allowing his or her expectations to affect the outcome of a study. |

Frequency distribution | A summary chart, showing how frequently each of the various scores in a set of data occurs. |

Histogram | A bar graph depicting a frequency distribution. The height of the bars indicates the frequency of a group of scores. |

Significant difference | Psychologists accept a difference between the groups as “real,” or significant, when the probability that it might be due to an atypical sample drawn by chance is less than 5 in 100 (indicated by the notation p< .05) |