Chapter 12 Flashcards
Central Tendency
A single number or value that describes the typical or central score among a set of scores.
Bar Graph
A visual presentation that uses bars to depict frequencies of responses, percentages, or means in two or more groups.
Correlation Coefficient
An index of how strongly two variables are related to each other.
-1.0 to 1.0
Criterion variable
The variable/score that is predicted based upon an individuals score on another variable ( the predictor variable). Conceptually similar to a dependent variable.
Descriptive Statistics
Statistical measures that describe the results of a study; descriptive statistics include measures of central tendency (e.g., mean), variablility (e.g., standard deviation), and correlation (e.g., Pearson r).
Effect Size
THe extent to which two variables are associated. In experimental research, the magnitude of the impact of the independent variable on the dependent variable.
Frequency distribution
An arrangement of a set of scores from lowest to highest that indicates that indicates the number of times each score was obtained.
Frequency Polygons
A graphic display of a frequency distribution in which the frequency of each score is plotted on the vertical axis, with the plotted points connected by straight lines.
Histogram
Graphic representation of a frequency distribution using bars to represent each score or group score.
Interval scales
A scale of measurements in which the intervals between numbers on the scale are all equal in sizes.
Mean
A measure of central tendency, obtained by summing scores and then dividing the sum by the number of scores.
Median
A measure of central tendency; the middle score in a distribution of scores that divides the distribution in half.
Mode
A measure of central tendency; the most frequent score in a distribution score.
Multiple Correlation
A correlation between one variable and a combined set of predictor variables.
Nominal Scales
A scale of measurement with two or more categories that have no numerical (less than, greater than) properties.
Ordinal Scales
A scale of measurement in which the measurement categories form a rank order along a continuum.
Partial Correlation
The correlation between two variables with the influence of a third variable statistically controlled for.
Pearson product-moment correlation coefficient
A type of correlation coefficient used with interval and ration scale data. In addition to providing information on the strength of relationship between two variables, it indicates the direction (positive or negative) of the relationship.
Pie chart
Graphic display of data in which frequencies or percentages are represented as “slices” of pie.
Predictor Variable
A variable that is used to make a prediction of an individuals score on another variable (the criterion variable). Conceptually similar to an independent variable.
Range
The difference between he highest score and the lowest score.
Ratio Scales
A scale of measurement in which there is an absolute zero point, indicating an absence of the variable being measured. An implication is that ratios of numbers on the scale can be formed (generally, these are physical measures such as weight or timed measures such as duration or reaction time).
Regression equations
A mathematical equation that allows prediction of one behavior when the score on another variable is known.
Restriction of range
A problem when scores on a variable are limited to a small subset of their possible values; this makes it more difficult to identify relationships of the variable to other variables of interest.
Scatter plot
Graphic representation of each individuals scores on two variables. The score on the first variable is found on the horizontal axis and score on the second variable is found on the vertical axis.
Standard deviation
The average deviation of scores from the mean (the square root of the variance).
Structural equation modeling
Statistical techniques that are used to evaluate a proposed set of relationships among variables.
Variablility
The amount of dispersion of scores about some center value.
Variance
A measure of the variability of scores about a mean; the mean of the sum of squared deviations of scores from the group mean.
