### Critical thinking

the process of assessing claims and making judgments on the basis of well supported evidence.

### statistical reliability

the degree to which test results or other research evidence occur repeatedly.

### Statistical validity

the degree to which evidence from a test or other research method measures what it is supposed to measure

### theory

an integrated set of propositions that can be used to account for, predict, and even suggest ways of controlling certain phenomena.

### Observational methods

procedures for systematically watching behavior in order to summarize it for scientific analysis

### Naturalistic observation

the process of watching with out interfering, as a phenomenon occurs in that natural environment

### Case studies

research methods involving the intensive examination of some phenomenon in a particular individual, group, or situation.

### Surveys

involve giving people questionnaires or special interviews designed to obtain description of their attitudes, beliefs, opinions, and intentions

### Correlational studies

research method that examines relationships between variables in order to analyze trends in data, test predictions, evaluate theories, and suggest new hypotheses.

### experiment

a situation in which the researcher manipulates one variable and then observes the effect of that manipulation on another variable, while holding all other variables constant.

### control group

in an experiment is the group that receives no treatment or provides some other baseline against which to compare the performance or response of the experimental group

### Confounds

in an experiment are any factors that affect the dependent variable, along with or instead of the independent variable.

### Random variables

confounds in which uncontrolled or uncontrollable factors affect the dependent variable, along with or instead of the independent variable.

### Randomizing

assigning participants in an experiment to various groups through a random process to ensure that rondo variables are evenly distributed among the groups

### Placebo

a physical or psychological treatment that contains no active ingredient produces an effect because the person receiving it believes it will.

### experimenter bias

confound that occurs when an experimenter unintentionally encourages participants to respond in a way that supports the experimenter's hypothesis (also looks at data differently?)

### double-blind design

a research design in which neither the experimenter no the participants know who is in the experimental group and who is in the control group

### Sampling

the process of selecting participants who are members of the population that the researcher wishes to study.

### Representative sampling

a process for selecting research participants who characteristics fairly reflect the characteristics of the population from which they were drawn

### Random sampling

the process of selecting a group of research participants from a population whose members all had an equal chance of being chosen. If a sample is not random, it is said to be biased.

### Biased sampling

the process of selecting a group of research participants from a population whose members did not have an equal chance of being chosen

### Epigenetics

the study of potentially inheritable changes in gene expression that are caused by environmental factors that do not alter a cell's DNA.

### inferential statistics

a set of mathematical procedures that help psychologists make inferences about what their research data mean.

### Mode

a measure of central tendency that is the value or score that occurs most frequently in data set.

### median

a measure of central tendency that is the halfway point in a set of data: half the scores fall above the median, and half fall below it. If even amount of scores, its half way between the two inner most data points.

### range

measure of variability that is the difference between the highest and the lowest scores in a data set.

### standard deviation (SD)

a measure of variability that is the average difference between each score and the mean of the data set. Highest - lowest =

### correlation coefficient

a statistic, r, that summarizes the strength and direction of a relationship between two variables