Measure of Center

is a value at the center or middle of a data set

Arithmetic “Mean”

a set of data is the measure of center found by adding the data values and dividing the total by the number of data values

Median

a data set is the measure of center that is the middle value when the original data values are arranged in order of increasing (or decreasing) magnitude

Mode

a data set is the value that occurs with the greatest frequency

Midrange

a data set is the measure of center that is the value midway between the maximum and minimum values in the original data set. It is found by adding the maximum data value to the minimum data value and then dividing the sum by 2

Range

a set of data values is the difference between the maximum data value and the minimum data value

Standard Deviation

a set of sample values, denoted by s, is a measure of how much data values deviate away from the mean.

Variance

a set of values is a measure of variation equal to the square of the standard deviation.

coefficient of variation

a set of non negative sample or population data, expressed as a percent, describes the standard deviation relative to the mean.

z score

is the number of standard deviations that a given x is above or below the mean

Percentiles

are measures of location,denoted p1,p2…p99 which divide a set of data into 100 groups with about 1% of the values in each group

Quartiles

are measures of location, denoted Q1, Q2 and Q, which divide a set of data into four groups with about 25% of the values in each group.

5-number summary

Minimum, First quartile Q1, seconf quartile Q2, Third quartile Q3, Maximum