Measures of central tendency the values around which set a set of the data tends to cluster.

There are several different kinds of calculations for central tendency; the kind of calculation that should be used depends on the type of data and purpose for which the central tendency is being calculated:

**But the three main types of central tendency are:**

**• Mean
• Mode
• Median**

**Mean:** **The sum of the values divided by the number of values—often called the "average."**

• Add all of the values together.

• Divide by the number of values to obtain the mean.

• Example: The mean of 7, 12, 24, 20, 19 is (7 + 12 + 24 + 20 + 19) / 5 = 16.4.

**Median:** **The value which divides the values into two equal halves, with half of the values being lower than the median and half higher than the median.**

• Sort the values into ascending order.

• If you have an odd number of values, the median is the middle value.

• If you have an even number of values, the median is the sum of the two middle values divided by two.

• Example: The median of the same five numbers (7, 12, 24, 20, and 19) is 19.

**Mode:** **The most frequently-occurring number.**

• Calculate the frequencies for all of the values in the data.

• The mode is the value (or values) with the highest frequency.

• Example: For individuals having the following ages — 18, 18, 19, 20, 20, 20, 21, and 23, the mode is 20.

** Outliers:** points in a set of data that are significantly far from the majority of the other data.

**Comments**

Maher and Kim: the chart you used to display the equations is awesome and the definitions are really helpful.

Comment:

By Osman Osman

Nicely done….. It realy made me have a better understanding about this chapter…. Thanx a lot

Peace *__*