Changes

The '''average''' is the sum of a group of numbers divided by the number of values in the group.  For example, the average of 3, 5, and 7 is <math>(3+5+7) \div 3=15 \div 3=5</math>.

The '''average''' is the sum of a group of numbers divided by the number of values in the group.  For example, the average of 3, 5, and 7 is <math>(3+5+7) \div 3=15 \div 3=5</math>.

Another term for average is the [[arithmetic mean]].

Another term for average is the ''arithmetic mean''.

==Other "measures of central tendency"==

==Other "measures of central tendency"==

*The [[median]] is the value which splits the group of numbers in the middle: half are higher, half are lower. The median is the most commonly used [[quantile]].

*The [[median]] is the value which splits the group of numbers in the middle: half are higher, half are lower. The median is the most commonly used [[quantile]].

*The [[mode]] is the exact value (or values) which occurs the most often in the group; in a continuous distribution, it is the highest peak.

*The [[mode]] is the exact value (or values) which occurs the most often in the group; in a continuous distribution, it is the highest peak.

*The average most commonly used is known as the ''arithmetic mean.'' There are other ''means.''

*The average most commonly used is known as the ''arithmetic mean.'' There are other ''means.''

**The [[geometric mean]] is used for "averaging" compound interest rates and in other percentage-growth situations.  

**The [[geometric mean]] is used for "averaging" compound interest rates and in other percentage-growth situations.  

**The [[harmonic mean]] is used when averaging speeds that are all measured along the same distance (rather than the same time).

**The [[harmonic mean]] is used when averaging speeds that are all measured along the same distance (rather than the same time).

**The [[root mean square]] is used in engineering power calculations, and heavily used in statistics in measurements of [[variance]].

**The [[root mean square]] is used in engineering power calculations, and heavily used in statistics in measurements of [[variance]].

==An example of average, median, and mode==

==An example of average, median, and mode==

Consider the number of chapters in each of the thirty-nine books of the Old Testament.<ref>Chosen because it is an example of a set of numbers that is far from having a normal distribribution.</ref>. Ranked in order by number of chapters, the list is:

Consider the number of chapters in each of the thirty-nine books of the Old Testament.<ref>Chosen because it is an example of a set of numbers that is far from having a normal redistribution.</ref>. Ranked in order by number of chapters, the list is:

:1, 2, 3, 3, 3, 3, 4, 4, 4, 5, 7, 8, 9, 10, 10, 12, 12, 13, 14, 14, 21, 22, 24, 24, 25, 27, 29, 31, 31, 34, 36, 36, 40, 42, 48, 50, 52, 66, 150

:1, 2, 3, 3, 3, 3, 4, 4, 4, 5, 7, 8, 9, 10, 10, 12, 12, 13, 14, 14, 21, 22, 24, 24, 25, 27, 29, 31, 31, 34, 36, 36, 40, 42, 48, 50, 52, 66, 150

*The thirty-nine books contain a total of 929 chapters, so the ''average'' number of chapters is 23.8.

*The thirty-nine books contain a total of 929 chapters, so the ''average'' number of chapters is 23.8.