Refers to a set of mathematical procedures for organizing, and interpreting information
The set of all the individuals of interest in a particular study
Set of individuals selected from a population, usually intended to represent the population in a research study
Characteristic or condition that changes or has different values for different individuals
- plural: Measurements or observations
Collection of measurements or observations
Singular: Single measurement or observation and is commonly called a score or raw score
A value, usually numerical, that describes a population. A parameter is usually derived from measurements of the individuals in the population
A value, usually numerical, that describes a sample. A statistic is usually derived from measurements of the individuals in the sample.
Statistical procedures used to summarize, organize, and simplify data
Consist of techniques that allow us to study samples and then make generalizations about the populations from which they were selected.
The discrepancy, or amount of error, that exists between a sample statistic and the corresponding population parameter.
Two different variables are observed to determine whether there is a relationship between them
Researcher manipulates one variable by changing it's value from one level to another. A second variable is observed (measured) to determine whether the manipulation causes changes to occur
Researcher must exercise control over the research situation to ensure that other, extraneous variables do not influence the relationship being examined.
One variable is manipulates while another variable is observed and measured. To establish a cause-and-effect relationship between two variables, an experiment attempts to control all other variables to prevent them from influencing the results
- Variable that is manipulated by the researcher, usually consists of the two (or more) treatment conditions to which subjects were exposed.
- The independent variable consists of the antecedent conditions that were manipulated prior observing the dependent variable
The variable that is being observed to assess the effect of the treatment
- The individuals within the condition do not receive the experimental treatment.
- Instead, they receive no treatment or they receive a neutral, placebo treatment.
- The purpose of the control condition is to provide a baseline for comparison with the experimental condition
The individuals that receive the experimental treatment
the "independent variable" in a non-experimental study that is used to create different groups of scores
Cannot be manipulated - Male/Female, Time etc
Defines a constructs in terms of external behaviors that can be observed and measured
Internal attributes or characteristics that cannot be directly observed but are useful for describing and explaining behaviour
- identifies a measurement procedure (set of operations) for measuring an external behavior and uses the resulting measurements as a definition and a measurement of a hypothetical construct.
- OD has two components:
- 1) Describes a set of operations for measuring a construct
- 2) Defines the construct in terms of the resulting measurements
- Consists of separate, indivisible categories.
- No values can exist between two neighboring categories
- 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
- The boundaries of intervals for scores that are represented on a continuous number line.
- The real limit separating two adjacent scores is located exactly half way between the scores.
- Each score has two real limits:
- The upper limit is at the top of the interval
- The lower limit is at the bottom
- 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.
- Race, gender, occupation etc.
Consists of a set of categories that are organized in an ordered sequence. Measurements on an ordinal scale ran observations in terms of size and magnitude
- 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
- Zero point on an interval scale is arbitrary and does not indicate a zero amount of the variable being measured
An interval scale, but with the additional feature of an absolute zero point. With a ratio scale, ratios of numbers do reflect magnitude