SOCIAL STATISTICS
Managing Data, Conducting Analyses, Presenting Results Fifth Edition
A measure of income inequality, typically within a society
Gini coefficient
A measure of the level of segregation between two groups, typically within geographic areas
Index of dissimilarity
A measure of variation used for nominal-level or ordinal-level variables
Index of Qualitative Variation, or IQV
The difference between the 25th and 75th percentiles
Interquartile range
Ratio of the change in the graphic and the change in the data. Ideally, given that the two of these should be the same, it should be around 1
Lie Factor
The sum of scores divided by the number of scores
Mean
The middle score in an ordered set of data for a variable
Median
The score that appears most frequently in a set of data for a variable:
Mode
A case that has a value on a given variable that differs dramatically from other values on the variable
Outlier
This Russian mathematician who figured out what proportion of cases fall one, two, and three standard deviations from the mean. Spelling it correctly not required!
Pafnuty Chebyshev
A close relative of the median, this has a certain percentage of the cases above or below it.
Percentile
The range in which one quarter of the cases in an ordered list of data fall
Quartile
The difference between the highest and lowest values of a variable
Range
The mathematical notation used to represent "add up all this series of numbers"
Sigma notation
The shape of a distribution that is not symmetrical, with the tail on the left side, meaning that there are some extreme lower scores
Skew to the left
The shape of a distribution that is not symmetrical, with the tail on the right side, meaning that there are some extreme higher scores
Skew to the right
The square root of the variance. It is useful for telling how unique individual cases are in a set of data
Standard deviation
A measure of variation for a ratio-level variable, it is the average squared deviation from the mean. It is useful for comparing the amounts of variation among various groups
Variance