
Statistics
a set of mathematical procedures for organizing, summarizing, and interpreting information

population
the set of all individuals of interest in a particular study

sample
set of individuals selected from a population, usually intended to represent the population in a research study

variable
characteristic or condition that changes or has different values for different individuals

Data
measurement or observations

data set
a collection of measurements or observations

datum
a single measurement or observation

parameter
a value that describes at population

statistic
a value that describes a sample

descriptive statistics
statistical procedures used to summarize, organize, and simplify data

inferential statistics
consitsts of techniques that allow us to study samples and then make generalizations about the populations

sampling error
the amount of error that exists between a sample statistic and the corresponding population parameter

correlational method
two different variables are observed to determine whether there is a relationship between them

experimental method
one variable is manipulated what another variable is observed and measured

independent variable
variable manipulated by the researcher

dependent variable
variable being observed

control condition
do not receive the experimental treatment

experimental condition
receive the experimental treatment

constructs
internal attributes or characteristics that cannot be directly observed but are useful for describing and explaining behavior

operational definition
identifies a measurement procedure for measuring an external behavior and uses the resulting measurement of a hypothetical construct

discrete variable
consists of separate, indivisible categories

continuous variable
infinite number of possible values that fall between any two observed values

real limits
are boundaries of the intervals for scores that are represented on a continuous number line

upper real limit
top interval

lower real limit
bottom interval

nominal scale
consists of a set of categories that have different names (labels and categorized observations)

ordinal scale
consists of a set of categories that are organized in an ordered sequence

interval sale
consists of ordered categories that are all intervals of exactly the same size

ratio scale
is an interval scale with the additional feature of an absolute zero point

