| A | B |
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| a hypothesis | A prediction about the relationship between two variables, asserting that differences among the measurements of an independent variable will correspond to differences among the measurements of a dependent variable. |
| a variable | A measurable phenomenon that varies (changes) over time or that differs from place to place or from individual to individual. |
| proportion | Part of the total amount or number of observations, expressed in decimal form. |
| statistical error | Known degrees of imprecision in the procedures used to gather and process information. |
| the statistical imagination | An appreciation of how usual or unusual an event, circumstance, or behavior is in relation to a larger set of similar events and an appreciation of an event's causes and consequences. |
| the field of statistics | A set of procedures for gathering, measuring, classifying, coding, computing, analyzing, and summarizing systematically acquired numerical information |
| a population (or universe) | A large group of people (or objects) of particular interest that we desire to study and understand. |
| a parameter | A summary calculation of measurements made on all subjects in a population. |
| a sample | A small group of the population; the sample is observed and measured and then used to draw conclusions about the population. |
| a statistic | A summary calculation of measurements made on a sample to estimate a parameter of the population. |
| fractiles | Scores that separate a fraction of a distribution's cases. |
| frequency distribution | A listing of all observed scores of a variable and the frequency (f) of each score (or category). |
| level of measurement of a variable | Identifies the variable's measurement properties, which determine the kind of mathematical operations (addition, multiplication, etc.) that can be appropriately used with it and the statistical formulas that can be used with it in testing theoretical hypotheses. |
| percentage frequency distribution | A listing of the percent of responses for each category or score of a variable |
| percentile rank | Among the cases in a score distribution, the percentage of cases that fall at or below a specified value of X. |
| proportional frequency distribution | A listing of the proportion of responses for each category or score of a variable. |
| quartiles | Fractiles that identify the score values that break a distribution into four equally sized groups. |
| representative sample | A sample in which all segments of the population are included in the sample in their correct proportions in the population. |
| simple random sample | A sample in which every person (or object) in the population has the same chance of being selected for the sample. |
| statistical error | Known degrees of imprecision in the procedures used to gather and process information. |
