Psych Stats Exam 1

heuristic

mental shortcut

availability heuristic

making decisions based on recent/available information

underlying assumption

the belief that things that are easy to recall are more correct/plausible

representativeness heuristic

used to estimate the extent to which a person or thing is representative of the average person in the category

gambler’s fallacy

tendency to think that a past outcome is relevant to a future outcome

law of small numbers

results based on a small amount of data are more likely to be incorrect

Illusory correlation

tendency to perceive a relationship when no relationship exists

Research goals:

Description, prediction, explanation

Description research goal

observation, case studies, surveys

Prediction research goal

correlational, quasi-experimental

explanation research goal

experimental research

Independent variable

the variable that the researcher manipulates

dependent variable

what the researcher is measuring

Population

the universe of scores that we want to generalize to (parameters)

Sample

a subset of the population (statistics)

Descriptive statistics

a set of tools for describing a sample (mean, median, etc)

Inferential statistics

a set of tools for drawing inferences about (generalizing to) a population

Sampling error

discrepancy between sample statistic and population parameter

Operational definition

a clear, concise detailed definition of a measure (operationalize)

Variable

numbers that convey information

measurement error

discrepancy between actual value and the measurement we get

Types of variables: NOIR

Nominal, Ordinal, Interval, Ratio

Nominal variable

Names- values are categories or binary variables (Y/N)

Ordinal Variables

Order- numbers stand for rank ordering. 1st place, 2nd place, 3rd place, class standing

Interval Variables

real numbers- numbers stand for equal amounts of what is being measured

Ratio Variable

0- an interval variable with a meaningful variable.

Continuous Scale

a variable that can be measured to any level of precision ex. weight

Discrete Scale

variable that only takes on a specific value on a scale

Reliability

consistency of measurement

Validity

accuracy: measure what you think you are measuring (hitting what youre aiming for)

Test-Retest reliability

scoring similarly on a measure completed at 2+ different times

Parralel forms reliability

test-retest when you cannot use the same form twice

Internal (split half) reliability

scoring similarly on different parts of a measure

Inter-rater reliability

agreement between different raters

Internal Validity

the quality of the study’s measures and manipulations

External Validity

the extent to which a study’s findings can generalize to other populations and settings

Statistical Validity

the appropriateness of the study’s conclusions based on statistical analysis