| A | B |
|---|
| Population | is the collection of all outcomes, responses, measurements, or counts that are of interest. |
| Sample | is a subset of a population. |
| Statistics | is the science of collecting, organizing, analyzing, and interpreting data in order to make decisions. |
| Parameter | is a numerical description of a population. |
| Statistic | is a numerical description of a sample characteristic. |
| Descriptive Statistics | is the branch of statistics that involve the organization, summarization, and display of data. |
| Inferential Statistics | is the branch of statistics that involves using a sample to draw conclusions about a population. |
| Qualitative Data | consist of attributes, labels, or nonnumerical entries. |
| Quantitative Data | consist of numerical measurements or counts. |
| Nominal level of measurement | data at this level are qualitative only. Data are categorized using names, labels, or qualities. No math computations can be made. |
| Ordinal level of measurement | data is qualitative or quantitative. Data can be arranged in order, or ranked, but differences between data entries are not meaningful. |
| Interval level of measurement | data can be ordered, and you can calculate meaningful differences between data entries. A zero at this level simply represents a position on a scale. |
| Ratio level of measurement | can be ordered, and you can calculate meaningful differences between data entries. A ratio of two data values can be formed so that one data value can be meaningfully expressed as a multiple of another. |
| Observational study | a researcher observes and measures characteristics of interest of part of a population but doesn't change existing conditions. |
| Experiment | a treatment is applied to part of a population and responses are observed. |
| Control group | a part of the population in which no treatment is applied. |
| Subjects | sometimes called "experimental units. |
| Placebo | a harmless, unmedicated treatment that is made to look like the real treatment. |
| Simulation | is the use of a mathematical or physical model to reproduce the conditions of a situation or process. |
| Survey | is an investigation of one or more characteristics of a population. |
| Confounding variable | occurs when an experimenter cannot tell the difference between the effects of different factors on a variable. |
| Placebo effect | occurs when a subject reacts favorably to a placebo when in fact he or she has been given no medicated treatment at all. |
| Blinding | a technique where the subject does not know whether he or she is receiving a treatment or a placebo. |
| Double blind experiment | neither the subject nor the experimenter knows if the subject is receiving a treatment or a placebo. |
| Randomization | is a process of randomly assigning subjects to different treatment groups. |
| Completely randomized design | subjects are assigned to different treatment groups through random selection. |
| Blocks | groups of subjects with similar characteristics. |
| Matched pairs design | subjects are paired up according to a similarity. |
| Replication | is the repetition of an experiment using a large group of subjects. |
| Census | count or measure of the entire population. |
| Sampling | a count or measure of part of a population. |
| Sampling Error | the difference between the results of a sample and those of the population. |
| Random sample | every member of the population has an equal chance of being selected. |
| Simple random sample | a sample in which every possible sample of the same size has the same chance of being selected. |
| Biased sample | a sample that is not representative of the populaton from which it is drawn. |
| Systematic sample | a sample in which each member of the population is assigned a number. |
| Convenience sample | a type of sample that often leads to biased studies. |
