## Data Distributions

Measures of central tendency describes how data clusters around a value.

**Mean****-**AKA the average, is the sum of the values divided by the number of values in the set.

**Median**-AKA the middle, is the middle value when the values in numerical order. If there are an even amount of data values, there will be two middle numbers. The median will be the mean of the two middle numbers.

**Mode**-AKA the most, is the value or values that occur most often. There may be one mode or more than one mode. There also may be no mode if no value occurs more often than another.

- The
**range**of a set of data is the difference between the least and greatest values.

When data is in order from least to greatest, it can be divided into

The

**quartiles**(4 equal parts). Notice each quartile has two numbers.The

**interquartile range**is the difference between the upper quartile, Q3, and the lower quartile, Q1.An

**outlier**is a value that is very different than the other values. The formula to find an outlier is 1.5 times the IQR plus/minus Q3/Q1.A

The lower quartile, or Q1, is the "median" of the lower half of the data while the upper quartile, or Q3, is the "median" of the upper half.

**box-and-whisker-plot**is a common way to display data. The lower extreme is the minimum value and the upper extreme is the maximum value. The middle quartile is the median of the entire set.The lower quartile, or Q1, is the "median" of the lower half of the data while the upper quartile, or Q3, is the "median" of the upper half.