Statistics in Psychology - Chapter II

A set of numbers whose properties model the empirical qualities of the objects they are assigned.

The property of "moreness." A particular instance of the attribute represents more, less, or equal amounts of the given quantity than does another instance.

The difference between two points at any place on the scale has the same meaning as the difference between two other points that differ by the same number of scale units.

Obtained when nothing of the property being measured exists.

A scale that only names or categorizes objects.

A scale that ranks objects according to magnitude but doesn't have equal intervals or an absolute zero.

A scale that has both magnitude and equal intervals but not an absolute zero.

A scale that has magnitude, equal intervals, and an absolute zero.

The raw, unmodified score of a test.

A visualization that shows how frequently each score occurs in a dataset.

A type of graph used for continuous data. It uses vertical bars to represent the frequency of each score.

A type of graph used for categorical data. It uses bars to represent the frequency of each category.

A type of graph used for continuous data. It uses a continuous line to connect points representing the frequency of each score.

The percentage of scores that fall below a specific score.

A specific score or point within a distribution that divides the total frequency into hundredths.

A statistic that represents the central or average score in a distribution.

The most commonly used measure of central tendency for interval and ratio data. It is the arithmetic average of all scores.

The middle score in a distribution, especially useful when the distribution has outliers.

The most frequently occurring score in a distribution.

An indication of how spread out or dispersed the scores are in a distribution.

The difference between the highest and lowest scores in a distribution.

The difference between the 75th percentile (Q3) and the 25th percentile (Q1).

A measure of variability equal to the square root of the average squared deviations from the mean.

A measure of variability equal to the square root of the variance.

A measure of the symmetry or asymmetry of a distribution. It indicates if the distribution is skewed to one side.

A measure of the peakedness or flatness of a distribution.

The performance of a defined group on a particular test. It provides information about performance relative to a standardization sample.

A bell-shaped, smooth, mathematically defined curve that is highest at its center. The mean, median, and mode are all equal.

A distribution of scores that follows the shape of a normal curve.

A raw score that has been converted from one scale to another scale with a set mean and standard deviation.

A standard score with a mean of 0 and a standard deviation of 1. It is the difference between a raw score and the mean divided by the standard deviation.

A standard score with a mean of 50 and a standard deviation of 10. It is a type of standard score that eliminates negative scores.

A standard score with a mean of 5 and a standard deviation of 2. It is a type of standard score that is used to summarize the scores of a large number of test takers.

A standard score with a mean of 5.5 and a standard deviation of 2. It is a type of standard score that is similar to the Stanine.

The strength of the relationship between two variables. It tells us the direction of the relationship (positive or negative) and how strong the relationship is.

A statistical test used to determine the strength of the linear relationship between two continuous variables.

A statistical test used to determine the strength of the relationship between two ranked variables.

A statistical test used to determine the strength of the relationship between one dichotomous variable and one continuous variable.

A statistical test used to determine the strength of the relationship between two dichotomous variables.