Frequency Distribution

A mathematical distribution whose objective is to obtain a count of the number of responses associated with different values of one variable and to express these counts on percentage terms with one variable considered at a times

Measures of Location

A statistic that describes a location within a data set. Measures of central tendency describe the center of the distribution

Mean

The average; that value obtained by summing all elements in a set and dividing by the number of elements

Mode

A measure of central tendency given as the value that occurs the most in a sample distribution

Median

A measure of central tendency given as the value above which half of the values fall

Measures of Variability

A statistic that indicates the distribution’s dispersion

Range

The difference between the largest and smallest values of a distribution

Interquartile Range

The range of a distribution encompassing the middle 50 percent of the observations

Variance

The mean squared deviation of all the values from the mean

Standard Deviation

Square root of the variance

Coefficient of Variation

A useful expression in sampling theory for the standard deviation as a percentage of the mean

Skewness

A characteristic of a distribution that assesses its symmetry about the mean

Kurtosis

A measure of the relative peakedness of flatness of the curve defined by the frequency distribution