Research & Statistics
Terms
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- Descriptive Statistics
- Numerical analysis that summarizes quantitive information about a population
- Cross-Cultural Studies
- Dealing with or comparing two or more cultures; "a cross-cultural survey"
- Bell Curve (normal distribution)
- A distribution of scores or other measurement values in which most values congregate around the median, and the measurement values rapidly decline in number on either side of the median, tailing off more slowly as scores get more extreme. The shape of a normal distribution resembles a bell, so it is sometimes referred to as a bell curve.
- Histogram
- A graph in which values found in a statistical study are represented by lines or symbols placed horizontally or vertically, to indicate frequency distribution.
- Control Group
- A control group study uses a control group to compare to an experimental group in a test of a causal hypothesis.
- Cross-sectional Studies
- A study in which a statistically significant sample of a population is used to estimate the relationship between an outcome of interest and population variables as they exist at one particular time. Since both the outcome and the variables are measured at the one time these studies are not strong at showing cause-effect relationships.
- Hypothesis
- A tentative explanation that accounts for a set of facts and can be tested by further investigation.
- Frequency Polygon (line graph)
- A graphic representation of a frequency distribution constructed by plotting each frequency above the score or midpoint of a class interval laid out on a base line and connecting the points so plotted by a straight line.
- Reliability
- The dependability of an experimental procedure, indicating that the procedure consistently yields the same results as long as it is administered in the same way each time.
- Longitudinal Study
- Research that follows a particular group of individuals (usually selected as a sample representing a population as a whole) over the course of time, often over many years.
- Range
- The full expanse of a distribution of values, from the lowest to the highest value.
- Standard Deviation
- A statistical measurement of dispersion, indicating the degree to which a set of values typically deviates from the mean value for the set.
- Correlation
- The statistical relationship between to attributes (characteristics of the subjects, of a setting, or of a situation), expressed as a number on a scale that ranges from -1 (a negative correlation) to 0 (no correlation) to +1 (a poitive correlation). A correlation is best represented by a scatterplot diagram.
- Validity
- The extent to which a given form of measurement assesses what it is suppose to measure.
- Sample
- For statistical purposes a small collection of individual units taken from the population which is under investigation on the assumption that they represent the characteristics of the entire population.
- Operational Definition
- A specific description of one or more precise elements and procedures involved in solving a given research problem, which allows researchers to communicate clearly the means by which they conducted an experiment and reached their conclusions.
- Median
- The middle score (half of the scores fall above and half the scores fall below) or other measurment value within a distribution of values.
- APA (American Psychological Association)
- This company advances psychology as a science and profession and as a means of promoting health, education, and human welfare
- Norms
- A fixed or ideal standard.
- Mean
- The average score within a distribution of values, computed by adding all the scores and then dividing the sum by the number of scores.
- Standard Deviation
- A statistical measurement of dispersion, indicating the dgree to which a set of values typically deviates from the mean value for the set.
- Dependent Variable
- The outcome response or attribute that varies as a consequence of variation in one or more independent variables.
- Correlation Coefficient
- A measure of statistical association that ranges from -1 (perfect inverse relationship) to 0 (no relation) to +1 (perfect positive relationship).
- Inferential Statistics
- One of two key ways in whic hstatistics are used, in which a resarcher analyzes numerical data in order to determine the liklihood that the obtained findings would have occurred solely by chance.
- Experiment (be able to design one)
- An investigation of cause-and-effect relationships through the control of variables and the careful manipulation of one or more particular variables, to note their outcome effects on other variables.
- Independent Variable
- An attribue that is individually manipulated by the experimenter, while other aspects of the investigation are held constant-that is, not subject to variation
- Mode
- The most frequent score or other measurement value within a distribution of values.
- Illusory Correlation
- An inferred perception of a relationship between unrelated variables, usually arising because the instances in which the variables coincide seem more noticeable than the instances in whic hthe variables do not coincide.