Master Chapter 1

“Population”

set of all the individuals of interest in a particular study

“Statistics”

value that describes a sample, usually derived from measurements of the individuals in the sample

“Parameters”

value that describes a population, usually derived from measurements of the individuals in the population

data

measurements or observations

“Sample”

set of individuals selected to represent the populaiton in a research study

datum

single measurement of observation; commonly called a score or raw score

descriptive statistic

procedure used to summarize, organize, and simplify data

inferential statistic

technique that allowd one to make geralizations about the populations from which samples were selected

variable

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

data set

collection of measurements or observations

lower real limit

boundary at the bottom of the interval

nominal scale

set of categories that have different names

ordinal scale

set of categories that are organized in an ordered sequence

upper real limit

boundary at the top of the interval

interval scale

set of ordered categories that are all intervals of exactly the same size

ratio scale

set of ordered categories wherein a zero score indicates none of the variable being measured

descriptive research

measuring seperate variables with the intent of simply describing the individuals variables

correlational method

observing two different variables to determine whether there is a relationship between them

continuos variable

value which is divisble into an infinite number of fractional parts

construct

internal attribure that can’t be directly observed but is useful for describing and explaining behavior

real limit

boundary of intervals for scores that are represented on a continuous number line

operational definition

procedure for measuring external behavior wherein the resulting measurements measure a hypothetical construct

sampling error

naturally occurring discrepancy between a sample statistic and the corresponding population parameter

discrete variable

value consisting of separate, indivisible categories, wherein no values can exist between two neighboring categories

experimental method

manipulating one variable while another variable is observed and measured

independent variable

value that is manipulated by the researcher

dependent variable

value that is observed to assess the effect of the treatment

control condition

group that either recieves no treatment or recieves a neutral, placebo treatment

experimental condition

group that recieves the experimental treatment

nonequivalent group study

score comparison method where the researcher does not control which participants go into which group

pre-post study

method of using the passage of time to create the groups of scores

quasi-independent variable

value that is used to create the different groups of scores

lower real limit

boundry at the bottom of the interval

interval scale

ordered categories that are all intervals of exactly the same size

ordinal scale

a set of categories that are organized in an ordered sequence.

ratio scale

set of ordered categories wherein a zero score indicates none of the variable being measured