Stats Chapter 1-2
Data
Information expressed as numbers
Rate
The number of actual occurrences of some phenomenon or trait divided by the number of possible occurrences per some unit of time. Usually multiplied by some power of 10
Ratio
The number of cases in one category divided by the number of cases in some other category
Proportion
The number of cases in one category of a variable divided by the number of cases in all categories of the variable
Midpoint
The point exactly halfway between the upper and lower limits of a class interval
Data Reduction
The process of using a few numbers to summarize many
Population
The total collection of all cases in which the researcher is interested
What are the four components of the wheel of science?
Theory, Hypotheses, Observations, Empirical Generalizations
Interval-Ratio
have actual numbers that can be analyzed with all possible statistical techniques
Nominal
have non-numerical "scores" or categories. Limited to comparing the relative sizes of the categories; must be mutually exclusive (no overlap between categories), exhaustive (place for every score), and categories should be similar
Ordinal
have scores or categories that can be ranked from high to low, so, in addition to classifying cases into categories, we can describe the categories in terms of more or less with respect to each other
Multivariate
Describes the relationship between more than two variables
Bivariate
Describes the relationship between two variables
What graphs are good for interval-ratio?
Histograms and line charts
Statistics
A set of mathematical techniques for organizing and analyzing data
Hypothesis
A specific statement, derived from a theory, about the relationship between variables
Percent Change
A statistic that expresses the magnitude of change in a variable from time 1 to time 2
Frequency Distribution
A table that displays the number of cases in each category of a variable
Independent Variable
A variable that is identified as a cause. Thought to cause the dependent variable
Dependent Variable
A variable that is identified as an effect or outcome. Thought to be caused by the Independent Variable
Cumulative Frequency
An optional column in a frequency distribution that displays the number of cases within an interval and all preceding intervals
Cumulative Percentage
An optional column in a frequency distribution that displays the percentage of cases within an interval and all preceding intervals
Variable
Any Trait that can change values from case to case
Research
Any process of gathering information systematically and carefully to answer questions or test theories. Statistics are useful for research projects that collect numerical information or data.
Sample
A carefully chosen subset of a population. In inferential statistics, information is gathered from one and then generalized to a population
Theory
A generalized explanation of the relationship between 2 or more variables
Line chart
A graph used for interval ratios
Histogram
A graph used for interval-ratio variables
Bar chart
A graph used for nominal and ordinal variables with only a few categories
Pie chart
A graph used for nominal and ordinal variables with only a few categories
Empirical Generalization
Made from trends in the data, might begin to develop ideas and observations when examining your original hypothesis
What graphs are good for any level of measurement? Mainly nominal and ordinal
Pie charts and bar charts
Quantitative Research
Research projects that collect data or information in the form of numbers
Measures of Association
Statistics that summarize the strength and direction of the relationship between variables; multivariate and bivariate
Univariate
Summarizes or describes the distribution of a single variable
Inferential Statistics
The branch of statistics concerned with making generalizations from samples to populations.
Descriptive Statistics
The branch of statistics concerned with summarizing the distribution of a single variable or measuring the relationship between two or more variables
Class interval
The categories used in the frequency distributions for interval-ratio variables
Stated Class Limits
The class intervals of a frequency distribution
Level of Measurement
The mathematical characteristic of a variable and the major criterion for selecting statistical techniques. Variables can be measured at any of 3 levels, each permitting certain mathematical operations and statistical techniques.
Level of Measurement
the mathematical nature of the variables under consideration