Stats 243 Ch 1-4

population

A _____ is the set of all the individuals of interest in a particular study.

sample

A ______ is a set of individuals selected from a population, usually intended to represent the population in a research study.

random sample

In a ______ ______ everyone in the population has an equal chance of being selected.

variable

A _____ is a characteristic or condition that changes or has different values for different individuals.

datum

A ______ (singular) is a single measurement or observation and is commonly called a score or raw score

data set

A ___ ___ is a collection of measurements or observations.

data

___ (plural) are measurements or observations.

parameter

A ___ is a value, usually a numerical value, that describes a population. A parameter is usually derived from measurements of the individuals in the population.

statistic

A ___ is a value, usually a numerical value, that describes a sample. A statistic is usually derived from measurements of the individuals in the sample.

descriptive statistics

______ are statistical procedures used to summarize, organize, and simplify data.

inferential statistics

___ ___ consist of techniques that allow us to study samples and then make generalizations about the populations from which they were selected.

sampling error

____ ___ is the naturally occurring discrepancy, or error, that exists between a sample statistic and the corresponding population parameter.

constructs

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

operational definition

An ___ ____ identifies a measurement procedure (a set of operations) for measuring an external behavior and uses the resulting measurements as a definition and a measurement of a hypothetical construct. Note that an operational definition has two components. First, it describes a set of operations for measuring a construct. Second, it defines the construct in terms of the resulting measurements.

discrete variable

A ___ ___ consists of separate, indivisible categories. No values can exist between two neighboring categories.

continuous

For a ___ ___, there are an infinite number of possible values that fall between any two observed values. A continuous variable is divisible into an infinite number of fractional parts.

real limits

___ ____ are the boundaries of intervals for scores that are represented on a continuous number line. The real limit separating two adjacent scores is located exactly halfway between the scores. Each score has two real limits.

upper real limit

The ___ ____ ___ is at the top of the interval, and the lower real limit is at the bottom.

nominal

A ___ ___ consists of a set of categories that have different names. Measurements on a nominal scale label and categorize observations, but do not make any quantitative distinctions between observations.

ordinal scale

An ___ ___ consists of a set of categories that are organized in an ordered sequence. Measurements on an ordinal scale rank observations in terms of size or magnitude.

interval scale

An ___ ___ consists of ordered categories that are all intervals of exactly the same size. Equal differences between numbers on a scale reflect equal differences in magnitude. However, the zero point on an interval scale is arbitrary and does not indicate a zero amount of the variable being measured.

ratio scale

A ___ ___ is an interval scale with the additional feature of an absolute zero point. With a ratio scale, ratios of numbers do reflect ratios of magnitude.

descriptive research/descriptive research strategy

___ research or the ___ research strategy involves measuring one or more separate variables for each individual with the intent of simply describing the individual variables.

experimental method

In the ___ ___, one variable is manipulated while another variable is observed and measured. To establish a cause-and-effect relationship between the two variables, an experiment attempts to control all other variables to prevent them from influencing the results.

independent variable

The ___ ___ is the variable that is manipulated by the researcher. In behavioral research, the independent variable usually consists of the two (or more) treatment conditions to which subjects are exposed. The independent variable is manipulated prior to observing the dependent variable.

dependent variable

The ___ ___ is the one that is observed to assess the effect of the treatment. The dependent variable is the variable that is measured in the experiment and its value changes in a way that depends on the status of the independent variable.

control condition

Individuals in a ___ ___ do not receive the experimental treatment. Instead, they either receive no treatment or they receive a neutral, placebo treatment. The purpose of a control condition is to provide a baseline for comparison with the experimental condition.

experimental condition

Individuals in the ___ ___ do receive the experimental treatment.

frequency distribution

A ___ ___ is an organized tabulation of the number of individuals located in each category on the scale of measurement.

percentile rank

The ___ ___ of a particular score is defined as the percentage of individuals in the distribution with scores at or below the particular value.

percentile

When a score is identified by its percentile rank, the score is called a ___.

central tendency

___ ___ is a statistical measure to determine a single score that defines the center of a distribution. The goal of central tendency is to find the single score that is most typical or most representative of the entire group.

mean

The ___ for a distribution is the sum of the scores divided by the number of scores.

median

If the scores in a distribution are listed in order from smallest to largest, the ___ is the midpoint of the list. More specifically, the median is the point on the measurement scale below which 50% of the scores in the distribution are located.

ordinal scale

An ___ ___ consists of a set of categories that are organized in an ordered sequence. Measurements on an ordinal scale rank observations in terms of size or magnitude.

central tendency

___ ___ is a statistical measure to determine a single score that defines the center of a distribution. The goal of central tendency is to find the single score that is most typical or most representative of the entire group.

median

If the scores in a distribution are listed in order from smallest to largest, the median is the midpoint of the list. More specifically, the ___ is the point on the measurement scale below which 50% of the scores in the distribution are located.

mode

In a frequency distribution, the ___ is the score or category that has the greatest frequency.

variability

provides a quantitative measure of the differences between scores in a distribution and describes the degree to which the scores are spread out or clustered together.

quartiles

are the scores having percentile ranks of 25%, 50%, 75%, and 100%, which are termed the first, second, third, and fourth ___, respectively. ___ divide the distribution into four equal parts such that each ___ section corresponds to 25% of the distribution.

interquartile range (IQR)

is the distance between the X values that correspond to the first (Q1) and third (Q3) ___. It reflects the range for the scores that fall in the middle 50% of the distribution.

variance

equals the mean of the squared deviations. ___ is the average squared distance from the mean.

sum of squares

is the sum of the squared deviation scores